Sorry to double post but I have finally prioritized my machine's features.
First to answer about graphics cards, @OP: You should really try to get a flagship graphics card. I know it's expensive as hell but it saves money in the long run cuz you don't have to upgrade and spend another chunk of money every year or so until your machine's abilities are maxed out.
Right now any of the nvidia 560 line are a great (probably best) deal for the money, or if you really want to be on the high end but still be on the margin of performance for your buck, go with an evega 580--just be prepared to receive sticker shock. Or you can go with the Radeon counterpart.
What's the difference?
The difference between Radeon and nVidia to my understanding is that while nVidia has a nice backwards compatibility with past games (a desirable trait as hassle with drivers can be a pain), Radeon is all about performing best for "games in the here and now". It's all a matter of preference of course.
So it matters what you'll be using it for.
There are some "better" ones than evega 580 but the $$$ paid for the performance gained IMO isn't worth it.
Far as my future machine: Performance/speed first and foremost. I doubt seriously I'll be overclocking because even with the best cooling it still reduces the life of your processor. Other than gaming, I might do some 3-d modeling and some hobby level microchip programming, some graphic art, picture editing. Probably music, movies and sound studio. So I may still need a core i7 if the other functions are to perform without slow down. We'll see.
What ELSE (besides gaming) are you going to be using your machine for, OP?