A laugh track for me can actually highlight how bad something is, I find. It I hear the laughing at jokes that are simply terrible, as is the case in a lot of modern sitcoms, then I just find that I notice how unfunny it is. Having said that, I like plenty of programmes with laugh tracks (Fawlty Towers, Blackadder, Frasier, etc). I think I might slightly prefer there not to be one, but that might just be because I've been watching a lot of 30 Rock, which doesn't have a laugh track, as of late and it hardly makes or breaks a show for me.