Many older printers may only have basic driver support, in which case you will lose maintenance utilities which show ink levels etc. Also, 64-bit support may be thin on the ground, and printers without 64-bit support will not work if connected direct or through a network to your new 64-bit operating system.

This is a list of the major printer manufacturer websites where you will either find good news or the prospect of having to buy new..

HP

http://h41112.www4.hp.com/promo/win7web/printer-support/us/en/deskjet.html

Canon -  (includes other Canon product lines)

http://www.usa.canon.com/app/pdf/Windows7_compatibility.pdf

Epson – this manufacturer prefers not to produce lists

http://www.epson.ca/cgi-bin/ceStore/support/SupportIndex.jsp?BV_UseBVCookie=yes

Brother

http://www.brother-usa.com/lp/windows7compatibility.aspx