Well, I'll use a little of existing things and a little of my own -
First, Amazing Johnathon is top notch, but it's mostly a one-view type of thing. He's hilarious, but he doesn't do much new usually. Puts on a GREAT show though.
Eddie Izzard is all over the place hilarious. If you can follow his train of thought, he can be one of the most rewarding comics out there.
Gabriel Iglesias isn't necessarily extremely funny, but he's a GREAT storyteller. In a similar vein, the puppet guy whose name eludes me at the moment is even less funny, but he's a GREAT puppeteer.
Mitch Hedberg is a classic and needs to be seen by anyone who likes stand up, and if you want his modern protege who also dabbles in some weird artistic stuff, definitely go for Dmitri Martin.
I've always had a thing for Brian Posehn - something about his goofy voice and weird attitude always struck me as being interesting.
I guess I'll have to end with Jimmy Carr, who can be offensive at times, but he's great at making some slick jokes.
Casual Shinji said:
H. Jon Benjamin
His voice alone makes him king.
He does stand up? Oh god I must see it! I'm looking this stuff up immediately!
Which reminds me, for a good sort of variety of stand up stuff with a little plot between, I highly recommend Dr. Katz. Love that show, and the small cast of regulars just have such great, er, voice chemistry, that I can't get enough of them. H Jon Benjamin of course being one of them. It's hard to be mad at him, even when he does something so mindbogglingly stupid you can't believe it.