Wheel Balancing

There's another thread where a member refers to going 43mph. At that speed, or even speeds lower than 43, are there not implications of "out of balance" wheels? We get our car's wheels balanced every time the tires are changed or rotated. I've noticed, even when using high end tires and tubes, that the wheels can be just slightly out of balance due to the presence of the stem, cyclometer magnet, or just irregularities in the tire. At high speeds, you can actually feel this in the saddle.

Does anyone actually balance their wheels and tires to eliminate these irregularities?