I like the Wichita rest with Protektor front and rear bags. Whatever you do, don't make the mistake of buying a rest that doesn't have some heft to it. The Wichita is solid cast iron and weighs in at around 13 pounds, so it's going to be very steady on the bench. Here's a link to it at Lock, Stock and Barrel:

http://www.lockstock.com/prodinfo.asp?number=WITCOMBO