Here are my suggestions. Im an intel fanboy, and even i would admit Amd can compete with intel up to the $200 dollar mark in cpus.
Its important to ask whats this gaming build going to be for, Is it mainly for starcraft 2? or do you want to play more wider array of games.
$600 can get you a good bit of bang for buck.
If you are building for sc2, i'd say focus on getting a better cpu as starcraft 2 is usally a cpu bottlenecked game. the graphic requirements are actually very light to play sc2.
Im not going to link any hardware pieces, as prices change all the time. But if i was you
i'd try to either get the AMD FX 8350 8 core processor , or an intel i5. Atleast that way you know the cpu wont ever be !@#$ for a long time.
for the motherboard you could basically get whatever is the cheapest model you see that supports the cpu socket.
for the harddrive, i not sure how much advice could really be given here, just take a look at segate or western digital and choose one you like . Seagate is generally a bit cheaper , so i'd go with seagate.
8 gigs of ram is pretty decently priced these days. The cheapest ram is probably the patriot viper 3 1600 mhertz 4x2 = #35. Its good ram!
For the gpu, there is where you can either save a ton of money, or spend alot of money. If sc2 is all you care about. Any %^-* gpu released with the last 3 years will destroy this game. You could spend as low as $70 to run everything in ultra graphics.
If you getting a gpu for lots of gaming and on a budget. The gtx 660 or radeon 7950 will be more than you need. The good thing about getting a good graphic card these days is that, next gen gaming is around the corner very soon, ps4 and xbox 720 are rumored to be releasing this year . getting a weak graphic card now, is more likely to show its age way faster than normal because of the shift to higher graphic games once ps4 /720 are rolled out. Most pc games are ports, therefore once the consoles start using higher graphics, the pc games will require higher graphics.
In my opinion, Budget you pc , but dont over budget, Because the more you cut, you could end up spending more in the long run by having to by parts entirely new compared to just upgrading . ( for the very least get that i5 or the 8core amd cpu) That way you know you wont have to upgrade the cpu. ( upgrading cpu usually means changing the entire board as well as the ram) Think smart on this one.
Edited by Incinerate on 1/18/2013 2:35 PM PST