Plustek 8100/ 8200. These are the old 7400 & 7600's respectively, same units, just the new model numbers are to reflect the update to Silverfast 8. The 8100/ 7400's come without dust removal, so are ideal for b&w only scanners, whereas the 8200/ 7600's come with built in dust removal, making them ideal for both colour and b&w.
Other than that, the flavours of Silverfast that come with them vary, with whether you opt for the Se or Ai version of the software. Se I believe will restrict you to 8 bit scans, with Ai allowing 16 bits scans which are the way to go for ultimate quality. Also if you intend to use Silverfast there may be other pertinent differences. Personally I deplore its user interface and use Vuescan instead, which although it has an equally poor interface, I know I will only have to learn once for any scanner I wish to use it with. You will however need to install the silverfast software to install the scanner drivers onto your machine. After that you won't actually have to use silverfast at all if you don't wish to.