You want something along the lines of this:
Nforce 4 Board
Athlon 64 3200+ Winchester Core- IIRC $128
1gig Corsair Value Select- $140
2x Seagate 120Gig SATA HDD or 1x 200Gig Seagate SATA Drive
OCZ Powerstream 420/ Seasonic SUper Tornado 400Watt
Seagate is arguably the best HDD manf (along with WD). Maxtor and Samsung though they are decent are found to be unstable and stuff. Just personal preference but i would get a Seagate. (WD Still has yet to move to fluid bearings). I would also advise to invest in a Seagate Barracuda 7200.8 as it supports SATA-II NCQ and has 16mb cache IIRC.
As for the memory 1 gig corsair Value select is 15 dollars cheaper and is higher quality RAM
The processor will OC farther than the 3500+ and is cheaper
As for the PSU it is no contest. That Thermaltake SUCKS. THe 18Amps on the 12V is pathetic and it is going to be very NOISY. Get an Antec Enermax OCZ Seasonic etc.
Im about to fall over from exhaustion (long day at school lol

) but i will find the prices and post them and compoare them to your current system in the morning. Sry cant do it now but HW calls
-Kevin