Besides my friend onezumi's hysterical eponymous strip*, which I will plug every chance I get, there's a lot of other quality webcomics I've been reading that you may like too. Click on the name for a favorite strip of mine for each comic. Keep in mind, some of these are actually serious works of fiction, rather than just for yuks.
Questionable Content is clever as hell, and has a nice sence of 20-something year old ennui. The art's particularly good on this strip.
Magical Adventures in Space is cartoony and goofy, but i love the odd wording the characters use... "gewgaws and curios"? I love it. Make sure you read the fine print under each comic.
If you're not reading Perry Bible Fellowship by now, I shall be forced to kick you in the crotch.
a softer world is a little jewel of photo and text, sometimes funny, sometimes achingly sad.
My current favorite, Nine Planets Without Intelligent Life, is a philosophical road trip undertaken by two robots in a solar system where man went out not with a bang, but a self satisfied grin. Picture 'Zen and the Art of Motorcycle Maintenance' as written by Bender from Futurama.
I think webcomics are to the oughts what graphic novels were to the 80s... a chance for creators to create with few constraints...