I wouldn't worry about it too much. Its easy enough to check if your scanner is compatible on the manufacturer's website, and anything new you get will have to be compatible. Like it or not, and I think in the long term you will like it, Vista is here and XP is gone.

Understand that not all hardware that you own will be compatible, but if you've got something recent, then its probably fine.

Here's the page for Epson to see if its compatible (you can download updated drivers from the site) http://www.epson.com/cgi-bin/Store/support/supAdvice.jsp?BV_UseBVCookie=yes&type=highlights¬eoid=86150