I agree it is a lot of fun to kill boosters, and its also very easy to do. Since they all cluster together its easy to get double or triple kills, and they are too busy trying to boost on each other to really notice you sneak up on them. But sometimes you don't notice there are boosters in a game until its too late and then a nuke gets dropped... I absolutely hate that.
Fortunately, from what I've heard Treyarch is going to severely crack down on boosting in Black Ops and will have teams going through games looking for cheaters. It will also be possible to record videos of cheaters and send that in as proof and then get people banned for it. So hopefully Black Ops will be less of a cheat fest and a more enjoyable experience.