I've just bought the same board with a 955 black. Also have the same chip in an Asus board.
Both overclocked to 3.6 and undervolted with no problems.
The only slight niggles I have with the Gigabyte board are that the power light doesn't flash when in sleep mode (Not the end of the world but it bugs me
) and the cpu temperature sensor seems to rise and fall a lot causing the fan speed to ramp up and down.
I know that sounds normal but the Asus doesn't have the same issue
Not a problem if you have a decent quiet cooler with a 'flatish' fan profile.
Any reason you don't want Intel? If you can run to the extra MB cost I would get an i5 k chip unless the extra 2 cores of the phenom will be specifically useful for you.
You have to be careful with the chipsets though.
H67 = Integrated graphics
P67 = Overclock multiplier
Z68 = Both of the above