I've had my current computer for about 2 years now. Honestly it still runs great for what I use it for (WoW and the occasional FPS although I'm not too picky about being able to play at max res/graphics.) What I'd like an opinion on though is if there is any one piece that would be a bottleneck and is holding the rest back. If I'd only see small gains from replacing different parts then I'll just stick with what I have but if one upgrade would show significant gains then it is a purchase I'd really look into.
WD Caviar Blue 640GB 7200 RPM SATA 3.0Gb/s
ASRock AM2+/AM2 AMD 790GX
OCZ 4GB DDR2 1066
EVGA GeForce 8800GTS (G92) 512MB
AMD Phenom II X2 550 Black Edition Callisto 3.1GHz Socket AM3
PC Power and Cooling 420W Power Supply
Windows 7 Ultimate
Edit: I unlocked my CPU's extra cores so it runs as a quad Phenom II X4 B50. Nothing is overclocked.