The D80's viewfinder is an immediately noticeable improvement over the D70/D70s. According to Nikon it's based on the unit in the D200 and the specs (0.94x magnification, 95% frame coverage) support that. It's bright, with no noticeable distortion and considering the DX (1.5x) crop still manages to fill your view. On the right side is a dioptre adjustment dial. The viewfinder also features the larger DK-21 eyepiece cup.

One big plus about the D80's viewfinder is its size: It's basically the same viewfinder as used on the D200, and is very noticeably larger than the viewfinders on other Nikon consumer SLRs. (The D70/D70S and D50, for instance.) The illustration above, courtesy Nikon, compares the size of D80's viewfinder with those of the Canon Rebel XT and the Sony A100 (both of which are approximately the size of the D50/70 screens). While I dislike having to press my eyeglasses up against the eyecup, all of us at IR really like having a larger viewfinder image to look at.
 
Here's another, more subtle point about the Nikon D80's viewfinder: It uses a true pentaprism, rather than the pentamirror arrangement that's all but universal in consumer-level SLRs. The reason this is important is that pentaprisms are much brighter. This is because a convenient trick of optics makes prisms 100% internally reflective, so no light is lost as it bounces around inside and back out the eyepiece. Even the best mirrors typically pass only 96-98% of the light falling on them. In a pentamirror, with three reflections required to bounce the light into your eye, this means that anywhere from 6 to 12% of the light is lost, making for a noticeably darker viewfinder image.

Another important new feature of the D80 is the adoption of the pentaprism viewfinder from the D200. This new eye-level optical viewfinder features large magnification (0.94x) that helps ensure a clear view for precise composition. The new diopter adjustment control knob also makes it easier to fine tune the view to match eyesight. The viewfinder's integrated grid display can also be turned on to assist composition.

One big plus about the D80's viewfinder is its size: It's basically the same viewfinder as used on the D200, and is very noticeably larger than the viewfinders on other Nikon consumer SLRs. (The D70/D70S and D50, for instance.) The illustration above, courtesy Nikon, compares the size of D80's viewfinder with those of the Canon Rebel XT and the Sony A100 (both of which are approximately the size of the D50/70 screens). While I dislike having to press my eyeglasses up against the eyecup, all of us at IR really like having a larger viewfinder image to look at.

Here's another, more subtle point about the Nikon D80's viewfinder: It uses a true pentaprism, rather than the pentamirror arrangement that's all but universal in consumer-level SLRs. The reason this is important is that pentaprisms are much brighter. This is because a convenient trick of optics makes prisms 100% internally reflective, so no light is lost as it bounces around inside and back out the eyepiece. Even the best mirrors typically pass only 96-98% of the light falling on them. In a pentamirror, with three reflections required to bounce the light into your eye, this means that anywhere from 6 to 12% of the light is lost, making for a noticeably darker viewfinder image.

Another important new feature of the D80 is the adoption of the pentaprism viewfinder from the D200. This new eye-level optical viewfinder features large magnification (0.94x) that helps ensure a clear view for precise composition. The new diopter adjustment control knob also makes it easier to fine tune the view to match eyesight. The viewfinder's integrated grid display can also be turned on to assist composition.

Scoop: Nikon D90 Specifications Revealed
As many of you know, I have a reliable source inside Nikon R&D. As such, I get detailed information about new Nikon models long before anyone else.
 
Without further ado, here are the details of the Nikon D90 DSLR, which is to replace the D80.
 
Universal Vibration Reduction (uVR)
The new D90 incorporates an optional feature called Universal Vibration Reduction (uVR). This turns all lenses into uVR lenses, and offers a 10-stop advantage.
 
This means a person using a 500mm lens, who would normally have to shoot at 1/500th of a second, can shoot at 2 seconds when uVR is enabled.
 
The new uVR system isn't sensor based, and instead requires one of the three optional vertical battery grips (see below). In this case, the MB-D90a is required. This grip provides all the normal controls and extended battery life of a regular grip. It also holds 8 EN-EL4a batteries, along with a step-up transformer.
 
With uVR enabled, the combined power of the batteries sends a current through the step-up transformer. This then delivers a 110 volt shock through metal pads around the grip. The resulting electrical shock matches the shutter speed (maximum of 10 seconds).
 
The shock causes a very stable clenching of the photographer's muscles while the shutter is open, simulating the stability of a tripod.
 
Nikon advise that people with rubber-soled shoes, heart problems or pacemakers shouldn't use uVR.
 
The uVR facility can also be controlled remotely by Nikon Support, via the new Nikon satellite network outlined below. This ensures Nikon Support can intentionally punish users who complain about how the new D90 is missing a particular feature they expected to see.
 
For example, the D80 didn't feature a military-grade titanium shell with platinum casing, and some people felt this was unforgivable in a camera that costs $900. Nikon Support will now be able to give those people exactly what they deserve.
 
Three shooting modes...up to 12MP
The D90 can shoot images up to 12MP, a modest boost over the D80 it replaces. While everybody agrees, more megapixels is always better, the D90 provides 12MP in only one of its three shooting modes. Here's a run-down on the various modes...
 
Bog-standard Mode:
12 regular megapixels at 3 frames per second.  
XDR Mode:
Every odd pixel is underexposed by 3 stops. Every even pixel is exposed as per the meter. The two images are combined in camera to produce an extra 3 stops of dynamic range at 6MP. This mode is especially useful in law enforcement, where photographers often have to photograph shady people.  
GTI Mode:
Every odd pixel makes up image one. Every even pixel makes up image two. That makes 2 images per shutter release, making it possible for Nikon's marketing material to claim the D90 shoots at 6 frames/second.  
Even better in-camera editing
The new D90 builds on the D80's popular in-camera editing functions. Rather than cannibalizing yet more features from Capture NX, Nikon decided to include a full working version of Photoshop CS3 in the D80.
 
We found using Photoshop CS3 on a 3 inch LCD with a 4-way controller much easier than you might imagine. Well done on a great new feature, Nikon.
 
To save money, the CS3 licenses were bought from a Russian spammer at 1/50th the regular price, allowing Nikon to keep the price of the D90 competitive.
 
More songs than ever
The D80 included an essential feature not found in any other DSLR (as I write this). And that's 5 built-in songs you can't listen to because the camera has no speakers.
 
The new D90 does away with built-in songs, and includes a fully-fledged iPod. This ensures you're never short of a tune, as long as you have your D90 with you. And it's switched on. And you've uploaded some songs to it.
 
What's more, the lack of speakers was the one thing almost everybody complained about. It was for this reason, and this reason alone, that DPReview spurned the D80, kneecapping it with a dreaded 'Recommended' rating.
 
That, and the limited choice of music included with the D80.
 
Sure, Nikon provided a firmware update that allowed us to add more tunes by storing them in the buffer...but that was too little, too late.
 
Fortunately, Nikon haven't made the same mistake with the D90. They've not only included stereo speakers in the camera itself, but also the necessary cabling for a full Dolby 5.1 surround sound setup. What's more, the D90 is capable of playing movies on the 3 inch LCD via the built-in DVD writer/player found in the second optional battery grip (MB-D90b).
 
But just before you rush out an get yourself an MB-D90b, you might want to consider the MB-D90c. This version of the grip includes a sub-woofer (fully compatible with the D90's Dolby surround). That's right, the optional MB-D90c allows you to play music with unprecedented levels of fidelity for a consumer-level DSLR.
 
Let's see Canon top that!
 
No more shutter delays
While the D80 was pretty responsive, your reactions aren't. By the time you've realized you should have pressed the shutter, the moment is lost forever.
 
The D90 solves this problem thanks to Nikon's new MindProbe technology. MindProbe scans your brain, looking for those tell-tale low amplitude beta waves that signal an imminent shutter-press. By the time your neurons react, and you actually press the shutter, the D90 has already captured 3 images (or 6 in GTI mode).
 
That's right folks, for the first time in the history of photography, the shutter delay is actually measured in negative time. Now that's progress.
 
My Nikon contact tells me their R&D people are now working on a system that eliminates the photographer altogether. Nikon's customer research has discovered that when a photographer takes a great image, they claim all the credit. But when a photographer takes a bad image, they blame the camera.
 
By eliminating the photographer, Nikon plan to eliminate lousy photos altogether.
 
New built-in artistic-effect modes
In addition to the regular scene modes, Nikon have included several artistic-effect modes. You can apply these to your image in-camera. Modes include...
 
Black and white mode  
1960s-style fast-film grain mode  
Nikon long-banding effect mode  
Canon plastic skin mode  
KM7D high ISO smearing mode  
Sony Alpha 1.3-stop underexposure mode  
Point and shoot artefact mode  
Memory card incompatibility solved
The D50 and D80 caused some controversy by moving Nikon's consumer-orientated DSLR models away from CF cards. This lead many Nikon users to resort to unseemly and ungentlemanly language in the forums (expressly forbidden under the terms and conditions of the standard Nikon warranty).
 
In an effort to avoid such distasteful events this time around, and ensure everybody can enjoy a D90, Nikon now supports the following storage formats...
 
SD  
CF  
XD  
Memory Stick  
3.5 inch floppy  
5.25 inch floppy  
8 inch floppy (in MB-D90b only)  
CD/DVD (in MB-D90b only)  
High-speed paper tape to maintain compatibility with Colossus  
Punch cards  
Wireless remote that works from anywhere
One of the complaints about the ML-L3 wireless remote, was that it was line-of-site. For some reason, you couldn't set up your camera in Texas, and trigger the shutter from France. Clearly, this should be well within the capabilities of a $15 remote control.
 
To answer these complaints, Nikon has put a series of satellites in orbit that are dedicated to receiving wireless remote signals from users anywhere on the planet. These are then forwarded to your camera, allowing you to trigger the shutter no matter where you are.
 
How long have we been waiting for this simple addition to the feature-set? Canon have had this functionality in their DSLRs for years.
 
Already in stores
After the fiasco over delivery of the D200 and 18-200VR, Nikon were determined to ensure they didn't suffer the same loss of face with the D90. That's why this new model is actually going to go on sale 5 days before the official announcement.

This means a person using a 500mm lens, who would normally have to shoot at 1/500th of a second, can shoot at 2 seconds when uVR is enabled.