Total: About $790
Add the i7 930, and the 2 HDDs:
New Total: $1180
I am not entirely convinced by the new 6gb/s yet and so would personally probably get 2 x Samsung Spinpoint F3 1TB, saves another $40.
The 5850 is a good card and is Direct X 11 compatible, seems a waste to buy an Nvidia card like the 275 which is old tech when you have a nice computer.
If you really want to get Nvidia though, I would go with the GTX470, while I am not a fan of Nvidias latest series I still consider it better than buying the old stuff. There may be some good combos with it.
If you do go Nvidia and you plan on SLIing in the future, you may have to get a more powerful PSU as they are power whores. The ATI cards will Crossfire with a 750W easily and leave room for OCing
I am no expert on monitors, I just go for a nice 1920 x 1080 of about 24 inches with 2ms response times, I don't worry about all the fancy extra bits as they add to the cost a lot, but I am sure someone here can advise.
So you think the GPU would be a bit of a bottleneck compared to the rest of the build? I noticed the 5850 does have significantly less power draw. I'll keep that in mind. Also, I forgot to mention the OS, but this is simple.
It's not so much it is a bottleneck - the 275 is powerful, its just it is old technology - Direct X 11 will only become more common, and $200 for a card that is not compatible with the latest tech (only manages Direct X 10) just seems a bit much, especially when ATI have some great cards out. Also, with your budget you could fit a GTX470 if you wanted to stick with Nvidia, so there is little reason to go with the 200 series