Before George Carlin exposed the seven words you can’t say on television, comedian Lenny Bruce was arrested multiple times for saying all seven, and more, on stage. Who is today’s most groundbreaking comedian? Or is there even any ground left to break?
Tough question. I think Lewis Black is one of the best around, but the angry blowhard is hardly a groundbreaking genre. Though he does it well, it's been done before.
Dane Cook has got to be THE most talented, hands down. Single best comic of his generation, though I hate it that he's said he'll never do stand-up again because making movies is soooo much easier, pays better and makes you more famous. It's a tragic loss, though I can't say I blame him.
Stephen Colbert gets an honorable mention. He's fantastic, but the Onion and Weekend Update beat him by a few decades. Even the Daily Show beat him...not so much the goofy talk show that Jon Steward hosts now (the one that is almost entirely propped up by The Best Fucking News Team Ever), but the deadpan delivery by the man who really made that show, Craig Kilborn. As the Daily Show moved away from that, Colbert took Kilborn's style and ran with it to great success. He may have even perfected it.
My vote here probably would go to Carlos Mencia. He does steal other people's jokes, which is lame. And he seriously tried to use the "Captain Redshirt" joke on one of his shows, which was an epic failure. May as well have asked why the chicken crossed the road. But his original material is hilarious, and it does break significant ground because he makes so many racial jokes that so many others would be terrified to even say in private amongst friends. He does so in an equal-opportunity sort of way, making fun of blacks and whites and Asians, as well as his own 'wetbacks' and 'beaners'. No one is offended. Everyone dies laughing. And no one else can do what he does so well.