Very interesting as I have a pretty powerful core i7 matx build as well, however, here is what I would have changed if I were you:
Case: Antec Mini p180 - much more room, especially if you remove bottom hard drive cage, can take ANY graphics then, much better cooling, and allows for REAL cpu cooler.
Motherboard: Asus Rampage II Gene - I used the DFI model then got the ASUS, its nicer, much nicer. Unless you need a couple specific overclocking things in BIOS, id recommend Asus board hands down, AND it has 2 firewire, one header, and one rear.
For those that care (probably not many but why not), here is my system:
Antec Mini p180
Corsair TX750 PSU (wish I had the $$ for the 1000 watt model used here)
LG GGC-H20L Combo Blu Ray Drive (same used)
WD 640GB Caviar Blue - placed in top optical drive slot - working on VR 300GB
6GB Corsair Dominator DDR3-1600 (saving for the Dominator GT DDR3-2000)
Dominator AirFlow Fan (triple channel model)
Intel Core i7 920
Lapped TRUE
5x Scythe S-Flex G fans (2 on TRUE, 1 exhaust, 2 intake in place of hard drive cages)
Thermaltake Extreme Spirit II Northbridge Cooler
2x EVGA GTX275 SLI (the SC models, even though I purchased stock clocks
)
This system hauls some serious ass, well staying reasonably cooled - although I will say that the S-Flex G fans have a noticeable hum to them. This system has run for days at 4GHz (50% overclock) with no issues.I "only" game on a 24" screen so the 2x GTX275 suffice for me. Thought about 295's in SLI but did not want to worry about the heat those can make (and the much higher cost).