I would probably be looking at an Intel Core2Duo E6750 and a Gigabyte P35 motherboard. Given how cheap RAM is these days, I see no reason not to go with 4 Gig (2x2048) even if you have a 32-bit OS. For a graphics card, go with either the 8800GT or the HD3870. For a hard drive: SATA 3.0 with 16MB cache. Size is up to you.