Mostly web comics, but there are others.
Questionable Content- really really funny web comic by Jeph Jacques about a group of friends. Think Coffee Shop of Doom, various sexual antics, random indie music references, and little robots running around. Updates Monday-Friday.
xkcd- hilarious and thought-provoking web comic by Randall Munroe. Stick people spitting out thoughts on tech culture, mathematics, physics, romance, pop culture, politics, everything! Updates Monday/Wednesday/Friday
(I will say, I have a personalized xkcd comic on my wall and a signed QC sketch as well- Aram and I nerded out and went to a comic convention this summer.)
Least I Could Do- an often terribly inappropriate but always terribly funny web comic that's been going on for like a couple years now- looking back at some of the storylines from a couple years ago can be really interesting. Updates Monday-Saturday.
A Softer World- Awesome web comic that puts dialogue to really well done pictures. Thought-provoking hilarity often ensues. Past storylines have included a werewolf that writes love poetry, a woman that grew out of a seed planted in the ground, and an extended storyline about people raising their mother from their dead and the resulting craziness from having a zombie mother. Updates Monday/Wednesday/Friday
Pop Candy- Great USA Today blog site from Whitney Matheson- she updates a ridiculous amount during the day. Lots of fun pop culture related items. This totally keeps me going to some of my classes - I know I can read it in it. It's really awesome.
Cake Wrecks- BEST BLOG EVER. Most addicting too. Beware: you will be laughing on the floor. Plus, if you start reading it- you'll probably find yourself going to the beginning and reading every entry ever.
And okay, I don't read this one every day because it hasn't been updated in forever- but Emo Animals is hilarrriousslyyy awesome. A friend of mine- Tierney- made it as a project for class. Check it out. Seriously.