Shooting with a digital SLR has always meant you had to carry a second camera, usually a point-and-shoot, because one thing that SDLRs have always lacked is video capability. But that's changed with Nikon's introduction of the D90 in August.
The D90 is the first consumer digital SLR to have video capabilities. (Canon has also announced a DSLR that can take videos, but it is one of its high-end cameras, well out of the price range of most non-professionals.) Video capabilities, along with other innovative features, are propelling the D90 to popularity among first-time DSLR owners and DSLR veterans alike.
High Image Quality, Low Noise
The video that a D90 takes is different than that you would get from a consumer video camera. The sensor on the D90 is much larger than that in most video cameras, so you get very high image quality and very low noise. You have the option of shooting in HD720p (1,280 x 720 pixels), 640 x 424 pixels or 320 x 216 pixels in MPEG format.
The variety of looks you can get with different lenses, such as from fisheye to long zoom also sets the D90's video apart. Unlike with traditional video cameras, you can stop down the aperture to get narrow depths of field. Watch this video for a demonstration of this capability.
What Works
This camera has many improvements over previous Nikon cameras and is ahead of the curve in the DSLR market in general. With many of the improvements introduced with the more expensive D3 and D300, but a lighter body and improved ergonomics, this camera is getting a lot of attention. At 12.3 megapixels the D90 has the same sensor as the D300, and many reviewers have reported that it has even better image quality. The 3-inch, high-resolution screen makes the camera a pleasure to view images on, and the live-view mode lets you compose your shots on the screen, rather than through the viewfinder only. Features you probably won't use as much are face-recognition auto focus, which can track up to five faces at a time, and in-camera editing.
How It's Different
The D90 does not behave like a typical video camera. It does not autofocus while you are shooting, so you'll need to focus manually and probably plan out your shots in advance a little more. It's not ideal for fast moving action, like sports games, because chances are you can't focus fast enough to track the movement.
Worth Buying?
With the features and ease of use it offers, the D90 is reasonably priced at $999, and you can save some money on a lens if you buy a bundled package. Overall the D90 is a very good DSLR with the added capability of video, which will open new doors of creativity for photographers used to shooting only still images.
A few images shot with the D90

true red by ientu on Flickr

KL Bird Park by chee.hong on Flickr
Stockhold by night by ientu on Flickr ientu