The "hop" you are referring to means that the wheel is ever so slightly out of true radially. A decent bike shop should be able to fix this for you for about thirty bucks or so, although the amount you describe would be acceptable to most people. This has nothing at all to do with the bike "bouncing" as you describe, which is indeed a consequence of the wheel being unbalanced. This is fairly normal, and most people don't give this a second thought, as it is harmless. It's mostly caused by the extra weight of the valve stem. Don't worry about it.