Linux i7 Rig for quiet stability and maybe a little Quake Live

I think you are going a little overkill here. For quake live you won't need more than an 7800 series nvidia card, and I know my 9600GT happily runs dual monitors (with compiz) and any modern games. Hell I had a Windows 7 partition for a while and the 9600 ran the Crysis demo with ~high settings at 1680x1050 at >20fps. I say step down a notch or two on the video card, you aren't really going to need the extra power and you can put that money into a second, larger hard drive for storing all your files that don't require the R/W speeds of a 10k rpm or solid state drive (music, movies, etc).