Could be bad ball joints too. My car has a bad passenger side ball joint and when you hit the brakes, there's a bit of side-to-side play in the steering wheel, and occasionally on a gradual turn while accelerating, there's a vibration/wobble from the front wheel. Best thing to do is put the front end up on jackstands and then check for play in the tie rods and pull down on the wheel and see if the ball joint clunks. That should tell you where your problem is. I wouldn't say it was brake rotors unless your brake pedal vibrates up and down as you apply the brakes.

Matt Campbell '87 245DL