Athlon 64 FX 55 2.6GHz, FX 57 2.8GHz or Dual Core X2 4800+ 2.4GHz (if you do a lot of multitasking)
Asus, MSI, or DFI (DFI has the best OCing but not as easy to use, also requires a solid powersupply) motherboards with the nForce4 SLI chipset (Socket 939)
Nvidia 7800GFX PCI Express card
Corsair or OCZ brand
PC3200 is standard although the FX57 can use faster memory without OCing LINK
I might consider PC4000 or PC4200 speed. Lower CL (CAS Latency) or timings is best. CL 2 is fastest then CL2.5 and CL3 is slow.
1GB is standard although you could consider going with 2 1GB sticks.
Western Digital 74GB Raptor 10,000RPM (I wouldn't recommend Maxtor)
Antec, Fortron, or Enermax Power Supply more than 500Watts
Don't skimp here. Most consider quality of the powersupply is just as important as the Watts. Other brands might have high watts or a high price but not many have as good of a track record as these brands.
Pick your case (Thermaltake Dream case is a nice new one. Lian Li makes light but quality cases)
Just typed that up before I have to head out. No links to parts yet. =p
www.cyperpowersystem.com is a very sweet site if your looking for any type of computer. Its has probably some of the best deals around. Yeah thats right im plugging this site now