There are so many awesome webcomics out there - this list will show you I'm all about the comedy though...
Tim Buckley's CAD began way back in October 2002 and will probably still be chugging along in one form or another way after the human race has gone...
#4. Strange Planet
Nathan W. Pyle gives us the everyday life of a family of adorable aliens. <3
#3. Tales of Absurdity
Tales of Absurdity is a weekly comic by Alex Hoffman that is so delightfully random it can't help but startle a laugh out of you!
#2. The Perry Bible Fellowship
PBF is a long running webcomic by Nicholas Gurewitch which specialises in 'sting in the tale' final panels. It's often kind of dark and surreal, but that only makes it better.
#1. Chief O'Brien at Work
Jon Adams' Chief O'Brien at Work is hands down my favourite webcomic. It follows Miles O'Brien during his seemingly neverending stint as transporter chief aboard the USS Enterprise-D. No matter how dull and meaningless your job, you can't help but feel better about it after a few panels showcasing Chief O'Brien's working day. :D