Hi Ro-Bot-X, nice to see you around 
I hope your robot will balance soon
Two axis accelerometer & one axis gyro are OK for the job
If you use separate breakout boards, make sure that axis are orthogonal, you may end up having the gyro board being perpendicular to the main board.
Also sensors units should match, don't fuse radian with deg/sec in your code
Finally the backlash we talked about is noticiable, but manageable
Please keep me informed of your progress, here
or there http://letsmakerobots.com/node/19558