I would recommend the Gigabyte DS3 mobo but it does not support SLI. For SLI, I'd recommend the EVGA nForce 680i mobo (no experience with it but it appears to be the best based on research I did).
PSU depends on what cards you will be running SLI. The Seasonic S12 Energy+ is a great PSU but will definitely not run 8800GTX SLI.
GPU: save some money and buy a single EVGA 8800GTX and overclock it rather than doing SLI.
Heatsink depends on your goals. If you want cool over all else, get a Tuniq Tower or Thermalright Ultra 120 Extreme (or wait for Thermalright's upcoming cooler). If you want cool and quiet, get the Noctua NH-U12F (also supposed to be very easy to install).
Motherboard, you are right. The psu can be boughten as long as you plan on using two cards. I ould look for one with the 8 pin PCI option, most will have 6+2 that works, and 4 PCI-e leads, the GTX takes 2 leads each. I like PP&C either the 750 or 1K aer great units, but the Enermax Infinty looks real nice also
An eVGA, BFG, XFX, ECS, or Biostar board are all nVidia reference design boards, and all are made by the same single contract manufacturer. I strongly suspect Foxconn's solution is a reference board also, but I havent confirmed this. The only difference is the box it came in, and a couple of bundled accesories. Im not saying its just the same circuits, Im saying it's even identical compenents.
There are five mainboard manufacturers developing their own designs around the 680i core logic- Gigabyte, MSI, Asus, Abit, and DFI (680i LT only).
Of these boards, most would agree that it's pretty even race between Gigabyte and MSI. Both have solid state capacitors. While the Gigabyte has a richer feature set (quad gigabit LAN, for example) the MSI has more PCIe 16x slots- a total of four. The Gigabyte, on the other hand, has more SATA ports, but the MSI has onboard X-Fi sound (solution from creative labs), the first board to ever do this.
Both are near impossible to get right now, but that will change. Both boards are floating in the $350-$400 range, dont pay more than that.
Whoever thinks the eVGA board is the best 680i solution out there didnt really do the research.
The EVGA 680i seems to be the best 680i board at a semi-reasonable price. I would never even consider spending anywhere near $400 on a motherboard unless it offered vastly improved performance and features over cheaper boards (none of the 680i do).
Personally, I don't think any of the 680i boards are worth the price. I've never been a fan of SLI and they offer almost nothing else over a 965 board.
680i boards are like $200. Still expensive for a board, tho. I'm not sure that those are great overclockers either. They have lots of features, though.
I would look at the 975X roundups and get one of those.
Maybe. I'll believe it when I see it. As near as I can tell, there is one announcement of the release date (this one) and one set of benchmarks. They are linked from multiple other sites. There is absolutely no official announcement anywhere that I can find.
I can't find any solid information on the R600. No consistent release date. No consistent price. No consistent performance. No consistent power requirements.
We should know very soon about the official release date. They just had a show for reporters last week, however there is an NDA on the event.
I have seen May 2 floating around as the day we should know what is going on (the end of the NDA, possibly?) and a release date of mid May (14th) for the XT. There are all sorts of crazy rumors flying about the XTX, so I have no clue about it. Hopefully in a week or two we will know the truth. Although you may not want to wait for the R600, you may want to wait for NVidia's response (8800Ultra). I have no idea when/if this is coming out, but I thought it was supposed to be right after the R600.
My current guesses on R600 (based on reading lots of rampant speculation and rumor) are:
[*:9bc2981ab0]Performance: 2900 XT/XTX will be on par with 8800 GTS/GTX.
[*:9bc2981ab0]Price: Cheaper than comparable 8800.
[*:9bc2981ab0]Drivers: ATI drivers will be less stable than nVidia (then again, aren't they always?).
On the 8800 Ultra, yep, it looks like a complete waste of money unless you have way too much money and just have to have the absolute top-end bragging rights...err...system (X6800, 8800 Ultra, etc).
Uh, I thought it was the opposite. ATI always releases good drivers and NVida garbage. I believe when the 8800 first came out its drivers were horrible. Even if that wasn't the case, ATI has supposedly had these cards cmpleted for months, so hopefully they have good drivers by now.