I don't game, so I don't need large graphics cards or PSUs.
I have 3 working Matx boxes and 1 ATX box at the moment.
1 stock Emachines T-5026, 2 Matx built by me, a G31 E2200 and a G43 HDMI / E6300 (the new Pentium Wolfdale). And last but not least, a P-45 ATX / E7300 / 9500GT built into an Antec 900.
All of the built by me machines are Gigabyte motherboards. (Accept no substitutes).
I wish there were more stylish Matx cases available. I have a Cooler Master "Centurion" and an Apex (the one with the carrying handle, if you've seen that).
I always feel that I've somehow failed my Antec 900, what with no RAID , no liquid cooling and no 9800GT card, but the blue fans are pretty, and it looks mean as h***.
Rather than "putting all my chickens in one basket" with one big expensive computer, I prefer to spread the tasks between them. You know, I think I'll play with this one today, that sort of thing.