The Intel® Core™ i5-2500K is the best performance/value processor on the market for a gaming system. The Intel Core i5-2500K uses socket 1155 which is our main stream socket for at least another year. The Socket 2011 is a high end enthusiast socket with quad channel memory support. For most of us the 6 core 12 threads of the Intel Core i7-3960x Extreme Edition isnt going to make much of a difference in a gaming environment. So the best advice that I can give you is to pick a good z68 and the Intel Core i5-2500K build from there.
What are you going to be doing with this computer? Recommendations can vary based on usage.
AM3+ will most likely die with bulldozer, the next AMD CPUs (piledriver) are supposed to be on FM2 socket.
Bulldozer was largely disappointing, but does a few things decently for the price.
LGA 1155 is supposed to be used for the upcoming Intel CPUs (ivy bridge), but motherboard compatibility is still unclear. Maybe IntelEnthusias has some more info on that...
AMD road maps are never accurate anymore, Bulldozer was suppose to be socket AM3, they changed it to AM3+ several months before launch. Piledriver is AM3+ or FM2 depending what roadmap you look at. AMD has stated it isn't profitable to design consumer oriented processors anymore, so expect their future chips to continue being best used in server work loads. And expect a completely new road map in February, so who knows if they'll even still make Piledriver. lol
Intel on the other hand, offers for better stock performance right now for a gaming build, and even better performance once overclocked. They have a huge lead over AMD in performance/watt, and a good lead in overall performance. Socket 1155 will be receiving 22nm Ivy Bridge in a few months, to only further the performance gap over AMD.
My conclusion, Intel and socket 1155 has much better longevity as a gaming platform than AM3+.
Piledriver is likely to be the final socket AM3+ CPU and it is expected to have a 10% performance increase over Bulldozer / Phenom II. That puts Piledriver at about the performance level of the 1st generation Core i3/i5/i7 CPUs. Ivy Bridge represents the 3rd generation of that CPU architecture.
If you're desperate right now, get the 2500K with a Z68 or a i3 2100 with a H67. Piledriver is going to be using a FM2 socket meaning it's going to be an APU. It will have both discrete graphics and a decent CPU targeting budget gamers.
Ivy Bridge isn't suppose to have a huge performance leap over Sandy Bridge and most 1155 mobos will support with a BIOS update when Ivy Bridge comes out. It is going to have a new line of mobos dedicated to Ivy Bridge like Z77 (I think). But as I said earlier, current 1155 sockets are going to be compatible with Ivy Bridge CPUs.
If you can, just wait till April and decide if you want a high performance Ivy Bridge, preferably a 3570k, or a budget gaming Piledriver CPU.
Ivy Bridge CPUs will most likely be priced like current Sandy Bridge CPU prices. Maybe $5 - $10 more, but I think that will not be the case. We will just have to wait.
Then again, I didn't think a quart of milk would increase in price from $0.95 to $1.55 in a span of 2 years, but it did (2008 - 2010). Now that's inflation!!!
Just hope that there will not be any natural disasters that will artificially increase CPU prices. The flooding in Thailand caused WD 1TB Black hard drives to more than double in price and prices are not expected to return to normal level until the end of 2012 or early 2013.