You'd be doing yourself a disservice if you went with that 9800 GTX+. The 4850 is $45 less after rebate, and it performs better. Also, Nvidia chipsets aren't as stable as Intel ones. If you insist on staying with that GTX+, decide whether you think you'll buy another one and SLI. If not, go with a P45 motherboard, like the Gigabyte GA-EP45-D3SL. I'd go with a Corsair 750TX instead of that OCZ PSU. The Corsair has a single 12V rail, which is always better, and it's only $100 after rebate. That being said, everything else looks great.
The 4850 Performs better? I thought it performs slightly worse than the GTX+, but at a better bang for your buck? No? I know the GTX+ is supposed to OC Very well and I worry about the heat problems with the 4850.
To be honest, I'd like to have the option of SLi, but there is a solid chance I won't use it. However, I'm having trouble find a board that's not Sli/Crossfire that isn't just trashed in it's reviews for various problems.
The OCZ PSU is actually a single rail, and after rebate, it's ten dollars more. That 750TX was actually the other PSU I was looking at.
the 4850s run hot because they set the fan so low. you can turn the fan up a decent amount b4 you start to hear it in a normal system. another reason for the 4850 is that nvidia is jumping on the DX10.1 bandwaggon with thier next set of cards, so DX10 won't have all the bells and whistles for future games
If you are set on a 9800gtx+, get a hybrid power motherboard. I'm pretty shure nVidia makes them for Intel now.
the hybrid power concept will turn your GTX on only when needed and use onboard graphics the rest of the time. should save lots of electricity.