Lewis Black, and John Stewart have to be my favorites.
A little offtopic, but I'm glad I stumbled on this topic, since I have a comedian related question. For the longest time now, I've been looking for a comedian I heard a long time ago. I don't remember his, all I remember is a small bit he did.
He started off talking about how he hates other parents parenting his children in stores. Goes off talking about a time that happened, from what I remember he said something like "So this woman starts parenting my screaming kid in the grocery store, I think to myself "What should we do?" "Call her a cunt" "You can't do that, your kid will hear it". Of course during this a firetruck drives by the store, my kid loves firetrucks, and just starts screaming when he sees them, but he's so young, he has a hard time pronouncing "firetruck", he sounds like he says "AWWFUCK"".
If something like that pops a comedian into anyone's head, that would be great to hear who you think it may be, been looking for a LONG time now.