I check monthly prices from PCX, Arctech, and PCQuickbuys (what? they're cheap there). And I don't think you could get a rig on 30K with decent SLI/Crossfire. 6600's are about P3500 each, and SLI/Crossfire motherboards are not coming cheap. Get a 7600 gt because that is the sweet spot for price and performance (i dont know one thing about ATi, so don't jump on me).
AMD's are very cheap right now, but if you can afford Intel Core 2 Duo, get one.
To get even cheaper stuff, you can see sale items in the Buy/Sell/Trade Section. There's lots of stuff there that might interest you.

There are ddr2 sales there.