My Gaming Machine
AMD Phenom II X4 B50 3.1GHz
4GB DDR3 1600MHz
GeForce 9800GT 512MB (OMFG hurry up with your DX11 cards!!!1one)
Primary HDD is a 150GB SATA drive (I forget the speed)

My Laptop
Intel Celeron 900 2.2GHz (CPUZ claims that it's a Core Solo Mobile)
3GB DDR2 400
Intel Graphics Media Accelerator 4500M 64MB
220GB SATA HDD (not sure of speed)

I did this for fun a while back
993MHz Pentium III
512MB PC133 (got it down to 192MB and it still ran)
GeForce FX5200 128MB
80GB IDE HDD
