I think the synopsis here is that if you're going P55, go P55 to save money now.
Based on your initial 2 specs chosen, I would 100% go x58. But, all-in-all I would go P55.
Explanation: If you're going P55, there isn't much value in going super top-end (P55 FTW 200 is high-end for a P55 board), if you are really into benchmarks and want to squeeze every bit of juice out of a build- go x58. If you don't mind giving up a few percentage points of performance (think 3-4%) for a 20%+ cost-savings, go P55.
I own the board that dndhatcher recommended, along with an i5-750 CPU. Highly recommend both and see little/no need to step up to the FTW 200 (as it means you pay a premium for the NF-200 chip, which tries to make a P55 board behave like an x58 board in the PCI-e lanes, but doesn't get you triple channel memory or hyperthreading). Now, both of these are of very little GAMING value- so really what you are doing is shelling out the premium to get x16/x16 SLI over x8/x8 SLI. The performance gain for this is generally stated to be significantly less than 10% (most figures quote 3-4%).
If you don't plan to SLI, then its easy- go P55. I got the EVGA P55 SLI model because it leaves the SLI x8/x8 option open in the future, and am very happy with the choice.
After looking at benchmarks the I7 870 is dominating the i7 930 at everything it does... ill keep my ram and 5770 and hopefully beable to sell my phenom x4 955 and ASUS M4A89TD Pro motherboard. When time comes for an upgrade to the gtx 470 then ill make my move..
DO note that X58/P55 is going to be replaced by Sandy Bridge soon, so if you can wait, do so.
If you want a system ASAP, grab a cheap AM3 CPU, board and DDR3 RAM now. Then sell CPU + board (or keep as a emergency spare) and upgrade when SB and BD comes out. You can easily get a Athlon II X2 + DDR3 RAM + ASUS/Gigabyte AM3 board for ~$250 or so.
Also, waiting on the ATI 6xxx may be a good idea too.
meh, its always a waiting game with these... wait a few months and something great will happen... then a few months after that, etc... computer never gets built.
Sandy Bridge isn't revolutionary... just Moore's Law in action. You'll see a performance bump on the processors- and integrated video that is getting closer to passable, but still worthless for anyone beyond casual.
Also, the chart that was linked are these processors at stock speeds- which does not account for the insane overclock potential of the i5 750/760, so expect that they end up much higher on the list when all is said and done....
^ The thing is, with the current sockets they will NOT receive any future upgrades. The sockets are done. For LGA1366 it will have one more refresh with 32nm CPUs, that's it. For LGA1156, it's done. Perhaps Intel will release more higher clocked/unlocked CPUs that's it.
Imo, there is no point in spending money when a platform is going to be history in a few months.
For the record, those of us that bought LGA1366 a few months after release have gotten good two years or so of use (Core i7 920 was released in Q4 2008) and the i7 920/930/950 is still at the top of the charts. That is until SB/BD comes out. Even then, it's still more than enough for most people.
Those of you getting LGA1366/1156 now will feel sorry when SB/BD comes out and not spending that little extra (obviously a few months ~2-4 after release) on the new platform.
Ati on the other and has nothing to offer with their 6xxx series just being a refresh of their 5xxx series.
Apparently the ATI 6770/6750 should perform the same as the 5830/5850 so we may have a noticeable change in the price vs performance segment for the $150-200 and $200-400 range. And we may even see the availability of 5770/5750 for <$100.
Well, how long should I wait? Just so you know, the more new things they release the harder it will be for me to sell my stuff, not to mention the value will decrease...ALOT. I don't even know what a sandy watever even is.. the 6xxx series seems to look like fail, but the Dual GTX 460 interests me... if you could get me more info then that would be great..
Wait depends on you. In two months if you will be upset that you could have got your same build for 10% less then wait, if not then dont wait. Also depends on how well your existing PC is serving your needs/desires.