I have basically just made the exact same build... see Sig Rig...
I'll say this.
My Asus Motherboard, I bought Open Box from Newegg; and thus far I have found that my Phenom II x4 955BE/c3 is very picky on this motherboard, with wanting slightly higher voltages; when compared to my Phenom II x4 940BE that I got a year ago.
My 955, prefers to be around 1.380v - 1.4v for; for stock 3.2ghz; and overclocking it on this board has been a real pain in the you know what. A straight Multiplier Overclock for mine, won't go beyond 3.4ghz without hiking up the Vcore pretty high. I can do 3.6ghz stable at 1.450v - 1.475v.
I am, somewhat regretful that I was not patient enough to wait for the 890FX boards being released this week.
Over all though, I am satisfied with my 955, my M4A89GTD Pro/USB3, my G-Skill Ripjaw DDR3-1600 kit, and my Sapphire Radeon card. My system is astoundingly fast compared to me previous Phenom II build! In fact my room-mate just bought the same motherboard, same RAM for his new Phenom II x3 720BE. Unfortunately we were not able to unlock his 4th core, but... his chip is running at a nice idle 23c, and is also astoundingly fast!
My 955, right now is idling at around 27c; and thats with an ambient room temp of around 68F; sitting 5 feet from an open window with an outdoor temp of 62F blowing a nice breeze through my room...
When outside is around 80F+ though, my ambient indoor is around 70 - 75 and my CPU's tend to idle around 36c+.
If you want to overclock that Radeon, don't get a Vapor-X. Thats an aftermarket cooling design, and the Reference designs are much better for overlcocking!