Ellen Degeneres is my all time favorite. I wish I could find some (any!) of her old stuff - before her TV show - on DVD. The only thing I have is her HBO special after she came out. Its fantastic.
IMO:
Eddie Izzard is God
Sean Connery is Noah
Anyone who does not believe in the greatness of the Eddie does not truly understand the Eddie. One of the things that makes him great is that he constructs his own in-jokes. He will say something at the start and it won’t be funny until 20 minutes later when he mentions it again. It suddenly makes sense, and the crowd goes wild.
However I also agree that Bill Hicks deserves a special mention as the most thought provoking comedian of all time. With Utah Phillips and Garrison Keeler as distant runners up.
peace
Currently touring: Jake Johannsen and Richard Jenni.
Golden Oldie: Robert Klein.
George Carlin for raw intelligence. His classic stuff, anyway; nowadays he’s just Angry Old White Guy. 
Robin Williams for sheer insane improvisation. Wish he’d do more standup and fewer movies.
A special fondness for Bill Hicks.
And a sympathy vote for Richard Tyler.
I still have some residue of the “women aren’t funny” mentality, but I realized yesterday that a couple of my favorites are women:
Sarah Silverman - Either she’s hysterical or I’m in love with her. Probably both.
Wanda Sykes - Not so good on Inside the NFL, and I haven’t watched her show, but her stand-up is top notch.
Ever heard Susie Essman’s stand-up? I’m almost 100% positive she’s who I am thinking of. GREAT delivery.
Yes I sure have, Voodoo, and I agree she is awesome. I couldn’t remember her name, and didn’t want to butcher her material trying to jog somebody’s memory.
(Is it “jog” or “jar”? Hmmm…mumbles incoherently)
Margaret Cho, baby.
“Are you gay!!! Are you gaaaaaaaaaaay? Pick up da phoooone! Ifa you… don pick up da phone… it mean you’re GAY. Be-cau-suh, only gaaaaay… screen call.”
I also love lesbian comedians such as Lea Delaria, Maggie Cassella, and Suzanne Westenhoefer.
Ooh, ooh, I love!!! Jake Johannsen!
‘I never look directly at them. I’m always afraid they’re going to riiiip they’re faces off…’
I haven’t seen him in years. I’m going to google to see if he’s coming anywhere close. Thanks!
Jake Johannsen is going to be performing in St. Louis at the Funnybone on November 6-8 and in Overland Park, KS at Stanford & Son’s on May 28-31. Who wants to go?
Thus proving the inaccuracy of your sreenname.
I like Eddie Izzard, Billy Connelly and Bob Downe.
It’s a close call between Billy Conolly and Eddie Izzard, but I think Billy just wins, 'cos I’ve loved him since I was a kid and he never fails to make me howl with laughter. Plus I’ve met him and he was a really lovely bloke - he gave me a big hug and a kiss! Eddie is more quoteable though: “Do earwigs make chutney? Do spiders make gravy”?
Bill Hicks is Christ Returned.
I wondered where Eddie went - seems he’s busy taking over the world! First time I saw him was The Secret Policeman’s Ball circa 1989 - a bit about a pack of wolves with four legs between them.
However, the single funniest piece of comedy ever performed, ever, is The Horn by Derek & Clive (ie. Peter Cooke & Dudley Moore). I know two people who foolishly put my tape of it on while driving and had accidents (fortunately just bumps).
I’m with you all the way with Sarah! It’s just that I have seen only one or two spots of hers on TV and those I just happened upon. I think the most memorable was a Bill Maher spot on his new HBO show in its earlier incarnation (not the one that just ended). She’s hilarious!
I disagree on Wanda, though. Not even funny.
Seinfeld
Ellen
Judy with the Curl (this is how she introduces herself)
Judi Tenuta
Rosie O’donnel was funny in her day
Dennis O’leary (He was in The Ref…hysterical movie)
Stephen Wright
Cosby ( in the early days)
Sinbad (before he themed everything from the 70’s)
I also want to come back in with a few second’s.
The Amazing Jonathan is silly, but hysterical.
I saw Patton Oswalt once on one of those dumb comedy telethons and thought I was going to pee in my britches. That guy needs his own show, right now.
George Carlin is also a genius.
And finally, Eddie Murphy in the Raw and Delerious days was untouchable.
They have (see Bill Hicks)
While Hicks is my all time favorite, he is obviously producing no more material (although the Iraq bits from “Rant in E Minor” are still suprisingly applicable).
So for curret comedians, I’ll second (or third) the nominations of Patton Oswalt and Mitch Hedberg.
Leary, Hedberg, Williams, Mark Curry, Carlin and Lea Delaria.
Hilarious!
Mitch Hedberg is the funniest commedian I’ve ever watched.
I got a chance to see him live last year, and I’m so glad I went. He truly is just a funny, funny person!!