Intel I7 970 (3.2ghz / 6-core), 16GB DDR3-2000, 2x Crucial M4 256GB SSD (and of course a traditional 7200rpm drive for not-currently-played Steam games), Nvidia GTX 580 /SLI, Dell Ultrasharp 27" (2560x1440), Windows 8 Pro (loving it so far!).
On the go:
Samsung 9-series Ultrabook w/Windows 8 Pro. Plays a few games (just has Intel 4000HD) - surprisingly X-COM and Guild Wars 2 run well at medium settings.