To whichever fool recommended over 2TB of disk space for one person: lol.
My build would probably look something like:
Asus Striker Extreme nForce 680i SLi
Intel Core 2 Duo E6700
2x XFX 8800GTX
4x 1GB Corsair Dominator 1142Mhz
Western Digital RaptorX 150GB
Western Digital Caviar RE2 500GB
Creative X-Fi Elite Pro
Logitech Z-5500 5.1 Wireless Speakerset
Totalling around $4,200 you can spend some additional money on DVD burners, mouse+keyboard, headphones, (water) cooling, etc. as you like. You could take 2GB memory and the speakerset out and it would save you about $750 lol.
But what I would do if I had that kind of budget, I wouldn't bother going for a PC case. I would buy an aquarium or another form of big glass case, and fill it with salad oil, and letting your components float in there for probably the best (but more importantly most awesome) cooling option.