I'm going to go ahead and say this is super overkill for a 16x9 monitor. Unless you need the i7 with HT for other non-gaming needs, the i5 line might be better suited or going AMD because they will perform well and not bottleneck whatever GPU you get.
As for the GPU, a 5830 will dominate the low resolution of your monitor. So unless you're planning an upgrade, you can cut down from the 5850. That being said, I love the value of pure FPS ATI can offer, but nVidia has a better product in end user experience. Its a shame PhysX isn't open source, but until Havok takes hold, team green and TWIMTBP offers a better experience.
My suggestion, is a 470 GTX with a i5 750. If you do upgrade your monitor, you'll be able to add a second GPU to maintain superior performance. Or go all the way with team read and get a PH IIx4 and a 5830.
Another thought, depending on what MMOs you play, an SSD as your primary drive might be worth exploring. SSDs generally don't raise performance in games except if you're playing an MMO where everyone has their own custom avatars. In MMOs, there's TONS of textures to load because of this little sash here and that trinket there. No way to pre load all that data when you're in a populated area and mechanical drives take much longer to seek than solid state drives. Just something to chew on.
I'll look into the different GPUs you're suggesting. My understanding was that the 5850 was the best card for the money - the 5870 appears to be a nominal increase for $100. When I started pricing, NVidia didn't seem to be able to compete for under $400, but I'll look again.
I will probably get a new monitor soon - I would like to run a dual monitor setup eventually. I'm thinking about a 27" primary and relegating my current to a secondary.
The main reason I wanted the i7 was I thought that I needed that to go triple channel. Can I get triple channel w/ an i5?
Well, the 5850 is a better value, especially if you're willing to OC because the 5870 doesn't have as much OC headroom. However, 5870 is still the better card overall, and I would absolutely suggest it, if you can afford it.
Just like the i5 or an AMD Ph II x4 won't bottleneck the GPUs you're considering, even in SLI/CF, dual channel memory won't either. The bandwidth is ample for real world apps in a dual channel set up and the memory system isn't what holds back gaming. This article compares 3 systems set up as close as possible except the ram. No rig walks away from the others and they all have their wins. Synthetic benchmarks sometimes favor the triple channel, but not always and again, that doesn't translate into real world performance. http://www.tomshardware.com/picturestory/511-memory-sca...
So if all your doing is gaming, triple channel won't do you any good, the i7 is more cpu than you need because the i5 750 will be all the power even a pair of 470s needs and the 8x/8x won't hinder the 470 sli set up. (480 comes close to maxing 8x/8x, so the 470s will be fine.)
If you do want the option of 470 sli, I'd get a little more powerful PSU. Full load with OC will come in around 650w-700w and that's running the PSU hard. 850+ would be my recommendation.
Do you need a cpu fan or going with the stock fan? If going stock, don't bother with the AS5.
For my last build (3-4 yrs ago) I remember people telling me "don't worry about getting a dual core - no games can take advantage of it anyway. just get the top of the line single core." Now I can't even play BFBC2 on minimum spec without at least a dual core. I have a feeling that the i7 and/or triple channel won't be overkill for very long...
I messed around on newegg tonight, and I can put together a comparable AMD box w/ 4 GB Ram for about $1k. I can afford up to about $1500, though, so I'd rather have the i7 and the triple channel, even if it's overkill now. I've always sacrificed processor for a better VC - now I can afford to get relatively higher end model of both.
I'm going to stick w/ the stock cooler setup - I really don't plan to OC. I have slightly OC'd all my AMD builds, but I'd rather not hassle with it - I want it to run well out of the box. People seem to agree that the stock fan is sufficient for the i7 unless you're going to OC.
After further messing on newegg, with combo deals and rebates I can get this set up for about $1130 - I don't think I can beat that balance of features & cost...
Looks good. Without OC, that setup with SLI will peak just under 600w. So that 750w PSU should do the trick. And since you're not going to OC, the stock goo on the intel HSF will keep your CPU safe, so you can drop the AS5 if you want, but that's not a huge expense anyway.