Well...in terms of performance/$, the 6950 is hard to beat. I didn't go the 6950CF route simply because Crossfire support isn't quite as good as SLI. When a game doesn't have a Crossfire profile, you're pretty much out of luck. When a game doesn't have an SLI profile, you can usually set it to a particular SLI rendering mode and get it to work (though SLI can cause glitches in some games without a profile).
I currently have 2x 570. If I had to do it again, I'd go with the single GTX 580 route, simply because I find the headaches of SLI are not necessarily worth it. I feel that a single GTX 580, with a nice aftermarket heatsink would be my preferred option at this point.
And as for the case, if you're thinking of a 932, you might as well get a HAF X instead, as it comes with the side panel cooling, and is a nicer case overall. Time to pimp my setup once more:
For the fan controller...I haven't heard great things from the NZXT. Probably better off getting a Scythe Kaze. I have the Lamptron FC-6. Not the best fan controller, as it's PWM (which makes controlling speeds a little more finicky), but it provides a ton of voltage, and looks nice on the HAF X case:
Viewing angles on it suck though.