You could go w/ a GTX 580 for around 500 bucks and SLI it in the future. This would not take you over your budget. I am also building a PC for a similar price. My wishlist is here: https://secure.newegg.com/WishList/MySavedWishDetail.as...
In my build I decided to go w/ the ASUS P868 Deluxe motherboard which is some of the best bang for your buck on the most recent Tom's Hardware Z68 Motherboard comparison... http://www.tomshardware.com/reviews/z68a-gd80-p8z68-del...
The Deluxe comes w/ bluetooth and high benchmarks for gaming.
I also chose to use the SilverStone Fortress FT02B-W. A super sick, and expensive case that has some of the best cooling, and greatest quality of all cases.
A video review for it here: http://www.youtube.com/watch?v=DMcKvI-zWi0
A lot of people recommend the Cooler Master Hyper 212, for a low price, supposedly offers great cooling and good for overclocking eventually.
Maybe few replies is a good thing. The guru's here must like your build. Good luck. Looks good to me. I think I might end up using the P8Z68 Pro also, since it seems more in line w/ the features I would actually use, and a bit nicer price point. Plus that Pro also has bluetooth which I have set my eyes on as a must have feature lol.