I'm rocking a quad core I7 960 (3.2ish ghz), 6GB tri-channel DDR3, NVidia GTX480 and some spindle drives for my main PC. The specs/motherboard were specifically selected so I could run Mac OSX on the machine (hackintosh) which I do with full 3D accelerator support in OSX. I actually hate OSX but it's for development and testing, Iphone as well, so I needed it. I also run Win7 64bit and WinXP 64bit from different drives on this system, but that's mainly for gaming and a bit of testing.

I'm using an AMD A6 5350M dual core APU laptop for my day to day, it's got a built in Radeon HD 8450G and 4gb dual channel DDR3, shared video memory. It's not anywhere near as fast as my desktop (Hitman absolution averages 16fps in benchmark!) but the GPU does contain the latest shader model structure so I can develop in GL4, which is far more than I could of expected from an Intel system at the same price-point.

It's very handy having both Nvidia and AMD GPU's to test code on - especially with GL4.x and various super new extensions. Plus the slower performance of the laptop gives me a good target to optimize for.