Used a tonymacx86 Hack Pro guide, unibeast install to Mountain Lion 10.8.2, upgraded to 10.8.3; Running the Mac Pro 3,1 system definition. Used guides and feedback from /r/hackintosh, as well as http://www.tonymacx86.com/
Uses OWC 120GB 6G sata for system drive, with automated weekly mirror to 160GB backup drive in case something goes haywire. I can boot to the backup drive, and write over the SSD.
The CPU is running overclocked to 3.8GHZ with no issues in stability or overheating on air cooling. Graphics aren't quite clocking where they should, but Steam \ CS GO runs full res at 120fps, so it's good enough. Thunderbolt works, although hot-swap doesn't work - the system needs to be powered on with a device attached. Plugging-in while running causes a hard freeze.
5 system fans, all 120\140mm. 1SSD, 4 HDD, no optical drives. 13" wide \ medium format printer, standard sized scanner, large wacom tablet. Old Sony DAV S300 home theatre system for sound - hooked up via optical.
Video editing is OK - going to upgrade to the i7 3770k. Didn't see Micro Center's deal on it before I bought the i5. Screenshots show idle and under load temps, which peak around 66-68C. This is during video conversion, with valleys between files. Right side shows activity monitor with load spread between the four cores.
Update: Decided to hold off on the i7 for now. Bought a Corsair H55i watercooling unit - I realize this is entry level, but I'm not trying to go crazy with the overclock. Stepped it up to 4.2 Ghz, and the voltage capped at 1.24v. With ambient air temp around 25, idle is around 35-38, with full load hitting 72. Prime 95 torture test ran it up to 80 degrees, but I doubt I would ever see that under normal circumstances. 4.2 Ghz was worth 15% performance boost over the stock clock, with no stability issues.