I've never seen Conan's standup.
I really like the STELLA guys
Michael Ian Black and Showalter are funny, but David Wain gets on my nerves. My roomate watches their DVD constantly.
There are a lot of good young/newer comedians out there in the "Comedians of Comedy" mold. Eugene Mirman
is a current favorite of mine. Aziz Ansari
is occasionally hilarious, but occasionally falls flat or just name drops annoyingly cuz he's soooo indie rock. Zach Galifinakis makes me laugh. I was high on Sarah Silverman for awhile, but I thought Jesus is Magic was kind of weak.
Still, funniest alive is probably Seinfeld. Eddie Murphy ("Delirious" era) close behind. Gaffigan probably takes it for comedians performing now, though I wonder if his stuff will endure.