Wow. Nice!
The guys at Maximum PC outdo my budget computer build, and in pretty good fashion, too. If you remove the cost of the video card (as none of my builds have that factored in) they undercut me by almost $82. Not shabby! Their best two cost savers are the power supply (since I was aiming towards something SLI/Crossfire capable) and the case.
Thinking about it, I think I'll likely drop the Crossfire/SLI from my list of things to really want. If I go with this, I'd make sure I had an AM3 motherboard (per the plan), a higher power supply (just in case), and I think that's about it. I'm not sure about the CPU... an Athlon II X3 would save some change and still get about the same gaming performance, whereas spending an extra $20 would get me a Phenom II X3 and get near i5 performance in some areas.
But wow... still. Good time for being a PC gamer!