I play medics in a lot of games, because in my experience it's the medic that contributes the most to the team's victory, whereas it's quite often the sniping types that contribute the least.
For example, Team Fortress 2 on 2Fort: it's the soldiers, medics, and heavies that bring back the briefcases. Demomen and engineers make entering your base a living hell for the enemy, pyros play it equally both ways, and the spy messes with well laid plans. I find that the snipers often plant themselves on the battlements and sling bullets back and forth at each other, not really accomplishing much. Sure, they help hold an area a bit, but they're not making the impact that other classes might at most levels of play. (I understand though that in the highest-end competition a good sniper is critical to stopping medic + x, but that's not most games).
This situation happens in a lot of FPS's: snipers sit and make kills, but often are too busy going for 'the perfect headshot'.