Lots of info there that I agree with bitlane. Some things that may be important though.
AFAIK, all 67xx and lower radeons are compatible with, and should use, 2.1 SDK. I have a 6770 mining happily on 2.1, probably because it's detected as a Juniper, the same as the 5770's that I have. Unfortunately I don't have ANY voltage control on that card, but thats besides the point (stealing the thread here.. anyone want to buy a 6770?
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Sapphire Trixx 4.3.0 may be less cumbersome for some people. I've never been able to underclock memory further than 600MHz with Afterburner. Sapphire Trixx now also supports undervolting. For dedicated miners though, I would only use software clock/voltage adjustments for the initial phase of finding optimum clocks, then later BIOS flash (back up the original VGA BIOS!) using the clocks and volts you want using RBE. I have 2 dedicated rigs and flashed the BIOS on all cards to optimum frequencies and volts, making reboots (if any) extremely painless.
CGMiner also may be more robust as far as features and being noob proof, but I also found that phoenix + phatk2 has speed leads on all other freely available miners when used on 2.1/2.4 SDK compatible hardware (have no clue with 7xxx cards, havent used them). Phoenix does not have fan adjustments though. In lieu of that, I use Glakkeclock to force a fixed fan speed of my choosing; it runs on OS startup inside a .bat file
All of my experience is on Win7 x64. I swear by 2.1 SDK, 11.12 OR 12.1 driver, Phoenix 2 miner, and phatk2 kernel.