You guys that are talking about $500 speakers and plasma TVs must not remember that he said he now wants to spend ~2,400. That's still enough to get basically all top of the line but no plasma TV. For that general price range I would get something like this,
DFI LP Ultra-D or SLI
A64 X2 +4400
7800GTX
2x1GB DDR 400 (PC3200)
X-Fi Xtreme Music
250GB Seagate Barracuda 7200.8 SATA150
17" or 19" Viewsonic LCD 8ms or lower
Antec TruepowerII 550W
^thats basically what I'm getting soon and when you throw in keyboard, mouse, case, and optical drives it comes to ~2,500.
and like Flanker I recommend a good set of headphones. I'm considering Sony's MDR-XD400 or Icemat's Siberia headset. If you want to go with surround sound speakers I'd say get Logitech Z-5300e 5.1 for a good setup that will fit in your budget.