My gaming PC/HTPC
Intel E2160 1.8 Dual Core - Overclocked to 3.1 Ghz. (Aftermarket CPU cooler)
ATi Radeon 4850 512Mb - O/C of course
250 Gig 7200 RPM Silent Seagate hard drive
500watt Hyper PSU
DFI P965-S Dark Mobo
4 Gigs of DDR2 800.
I've got that hooked up to a Dayton APA150, powering my custom bookshelf speakers (TB W5-704 + Dayton Silkie tweeter), and I've got a Mach5 MAW15 sub powered by a 250 watt plate amp. In a 11*12 room it does okay. Extension down to ~12Hz, but it's just too big in this room.