I recently ordered a Canon Canoscan FS2720U film scanner. Here are my thoughts on it:
At the price ($330 including shipping from Adorama.com )it was a steal, half the price of most other scanners I had considered. This also includes a limited version of Adobe Photoshop, hence giving enough power right out of the box to process the images (though I already owned the full version of photoshop). The USB 1.1 interface, though a bit slow for these large files, is usable with nearly any computer nowadays. The color depth is fine (24 or 36 bit color--any scanner cheaper than this probably won't deliver such color depth, and you shouldn't consider anything less than 24 bit. The 36 bit scans do give slightly better quality on some of my negatives). It scans both 35 mm negatives and slides.
It's not meant for high-volume use. You have to feed it one slide at a time, or select one negative from a film strip (strips can be up to 6 images long). It is possible to do some processing before scanning, such as adjusting color balance, brightness, or more specific brighness adjustments ("levels" or "curves") to squeeze the most information out of your negative.
The resolution of 2720 dpi was near the bottom of my acceptable range, but that's high enough to give an absolutely sharp 8"x10" enlargement, or a just-barely-fuzzy 14"x20", assuming that your negative was not grainy. It's plenty high enough resolution for the majority of work, and for 5"x7" prints lower resolution would do (you can select resolution down to 72 dpi).
I have no doubt that my local pro photo shop has a better scanner, but I've dumped them because I get better results at home with my cheap scanner. No doubt this is because I know what I'm looking for in a scan, whereas they aren't familiar with optimizing night-sky photos.
The February '02 Sky & Telescope gives good hints on how to use a film scanner.
Bottom line: at the price, I'm betting the Canoscan FS2720U is the best buy on the market, and good enough to keep me happy with film for another couple of years until the price of CCD cameras falls out of the absurd range (no CCD costing under $5000 can deliver the resolution I get from film at 2700 dpi). I like my scanner a lot.