As for a board, there were ones earlier. My two favorites were the ASRock P67 Extreme4 ($150ish) and Asus P8P67 Pro ($190ish). Whenever new versions of those are released, those would be what I looked at first.
As for PSUs, I'd go with a high quality 850W. I like either the XFX 850W for $126 (with shipping and rebate) and the SeaSonic 850W for $125.
If you can find one of the flawed MBs, yes you can use it just fine if you connect your HDD and optical drive to the 6G ports, which are backward compatible with 3G devices. But at this time you might as well wait for the new revisions...
thank you all for the replies, i will get the ddr3 1600 ram instead of 2000, also i dont think i will be doing SLI because its expensive and i'm always under the impression that it will only give about 30% more performance increase.
the XFX 850W seems good, i just dont know how much watt will i really need.
You'd want at least 850W for SLI. You definitely wouldn't need the 1000W that Jack's recommending. If you're 100% sure you never want to try SLI, you could drop that to a 650W model. Check out Antec, SeaSonic, Corsair, Silverstone and XFX's choices at that wattage.
I would suggest that you consider keeping the option to SLI open. You don't end up spending that much more for the opportunity, usually about $20-30 on the board to get a second PCIe 2.0 slot at 8x and maybe $20-30 on a larger PSU. SLI generally improves performance by 60-75%, depending on the game and the drivers. It's not something you'd want to start a build with, but it's a great option later on in the build's life.
Look at it this way. In 3-4 years, when a single GTX 580 is beginning to show it's age, your two options for upgrading performance are to either buy a brand new card or add a second 580. A new card will likely run another $500+, and might give you 50% added performance, but come with new features (new DirectX versions), which aren't likely to be standard yet. Or you could buy a second GTX 580, likely for around $250, and get 60-75% more performance, but you wouldn't have those new features. The second 580 would likely tack on another 2-3 years of life to the build, at which point you'd have to replace the entire machine. You'd also get another 2-3 years with the new single card, which you could carry over to a new build for a short while, if you wanted to get similar performance out of your new machine.
@Jack: Why do you always recommend the ridiculously overpriced HAF X? It's $200, and you don't get anything useful for it over the $120 HAF 932 or $90-100(ish) HAF 922. The only added features the HAF X has is an added two expansion slots (which you will NEVER need), one LESS 3.5 bay, one more 5.25 bay (over the 922 only), two slighly bigger fans (230 mm vs 200 mm) and one more fan (than the 922). The X isn't even that much bigger. It's 23.2 x 9.1 x 21.7, while the 932 is 22.70 x 9 x 21.50 and the 922 is 22.20 x 10 x 19.7. That's really not a lot of useful space. It's a horrible deal.
Here is a list of sub $200 cases that are all better choices than the HAF X: Silverstone Raven RV02-BW, Coolermaster's Cosmos S, Antec Lanboy Air (massive cooling), and Antec 1200 V3. Those are only the overly expesnive ones, and only considers performance. If you considered how much better they look, all four of those would be a steal compared to the HAF X. If you included price, I'd have to throw in the Antec 900, HAF 932, HAF 922, any Lian LI and Coolermaster's 690 II. They are generally smaller, but they're much more attractively priced. Any of the first group would fit the needs of someone who would actually need something like the HAF X, while the second group would fit the needs of any gamer.
As for spending $70 to get 16x/16x, that's also a horrible idea. The performance difference between 16x/16x and 8x/8x is only 3-4% at the most. Tom's did an exhaustive review of it a long time ago. They also found that the only card that it would actually make a material difference for is the HD 5970 is Crossfire. The GTX 580 is a lot less of a card, so it would matter less. And just to point out, that 3-4% really only equates to 1-2 FPS. That's definitely not worth $70.
thank you all again, what you guys think about the incoming GTX590? personally i take nvidia over ati anyday, but i heard gtx590 will be 100$ more expensive and the cores are downclocked, so they are slower than 6990?