I'm not a scanner expert (I have an old $75 Agfa that I just use on very rare occasions).
However, the March 2003 issue of Macworld has a big scanner feature in it, comparing and reviewing 2 models each from Epson, HP, and Canon. You may want to check that out (the reviews should be online at
www.macworld.com too). For the record, the Epson Perfection 2400 Photo and the HP Scanjet 5500c got the best ratings (4/5).