Searching for a scanner with a robust Twain driver can make operation easier and more enjoyable. Watch out for expensive software bundles which you may not need, such as the full version of Adobe Photoshop. Usually manufacturers will offer two different packages in such cases. Flatbed scanners are the way to go if you plan to scan a variety of images rendered on various materials. Some require a SCSI card in which case you will need an available slot.
SCSI scanners are faster than scanners running through a parallel port.
Prices for color scanners are continually falling. For an idea on recent prices check out Buycomp's Scanner page . All pics that were scanned on my elfwood page were done by this scanner. You do not need a more expensive one if all that you are doing is web graphics and home use. The trick is to make sure it works well before you take it home.