Need New Mid- Level PC, any suggestions?

[Shafra]

Hello all, looking for to build a second PC just for net serfing, music playing, and some video encoding. Here's what I do have, and would like to keep and use this stuff if possible.

550 Rosewill PSU
Rosewill ATX Case
SB Audigy
250GB MAxtor Sata Drive
256MB AGP Nvidia 5700LE (It seems ok for this build if I can use it)

So that's what I have, guess I would need some ram, a mobo, and a CPU. Open to any suggestions, I know nothing about the new Core DUO CPU's, and if I needed to get a cheap PCIE vid card feel free to recommend one of those too!

Really appreciate any help. Usually shop through NewEgg so if you have any links that would be great too

 

[Nukem]

what's your budget for the rest of the parts...

Epox Ep-9NDA31 S939 - 59.00
http://www.newegg.com/Product/Product.asp?Item=N82E16813123263
Opteron 144 Socket 939 - 79.00
http://www.newegg.com/Product/Product.asp?Item=N82E16819103600
pqi DDR400 PC3200 (2x512MB) - 98.00
http://www.newegg.com/Product/Product.asp?Item=N82E16820141212
Coolermaster Centurion 5 - 55.00
http://www.newegg.com/Product/Product.asp?Item=N82E16811119077
Linksys KVM switch - 32.00
http://www.newegg.com/Product/Product.asp?Item=N82E16817107702

The KVM is for dual system, but only one KB/M and monitor... comes in handy... I have one and it works very well...