WdnUlik2no

I built my first PC over 5 years ago, and while it still going strong, I think it's about time for me to build another.

my current build

MSI K8n-Neo Platinum
AMD Athlon 64 3700+
2 GB RAM Cosair Select
Ati Radeon X800 Pro (AGP)


At the time this build was probably a mid range comp, so I'm looking to build another mid range or upper mid range comp that is the best bang for the buck and something that will run Starcraft 2 very smoothly whenever it comes out.

Since I haven't been keeping up with the new technologies, I'm a little in the dark about what I should look into getting. I would like to stay with AMD if possible.

Price wise I would like to stay in the $500 - $600 range for everything (not including case); but that is not set in stone.

Suggestions please; mainly on the processor/MB/and video card, I think I can figure the other stuff out.