Contributor(s): Jama Courtney
Note: This information is dated July 2007, and will be good for about a year, year and a half.
For a dedicated 35mm negatives (standard sized and not over-sized), I would recommend the Nikon SuperCoolScan5000 ED http://www.bhphotovideo.com/c/product/310477-REG/Nikon_9238_Super_Coolscan_5000_ED.html $979.00
A less expensive alternative is the Nikon Coolscan V ED (not as high a quality in that it doesn't capture as well the subtleties in very dark shades) http://www.bhphotovideo.com/c/product/310476-REG/Nikon_9239_Coolscan_V_ED_Film.html $549.00
Another alternative is to get a flatbed that does negatives such as the Epson 700 or the Microtek i900. I have no personal experience with either of the two listed below.
I just purchased an Epson Perfection V700. http://www.bhphotovideo.com/c/product/426013-REG/Epson_B11B178011_Perfection_V700_Photo_Flatbed.html $519.00
I intend to use it predominantly for prints and occasionally for negatives. I rarely do medical imaging anymore (where I would want/need the Nikon. Also when I do these types of slides, oftentimes, they are odd-sized.)
I SERIOUSLY looked at the Microtek i900. $469 I had a Microtek scanner a few years ago, and I really liked the interface, the quality, and they usually run a little less than Epson. Also, the longer "legal sized" bed is nice. I purchased the Epson out of habit.
Note that The Coolscans are dedicated film scanners and do not scan prints. The Epson and the Microtek do both film and prints.