Seconding Order of the Stick!

Also Darths & Droids:

http://www.darthsanddroids.net/episodes/0254.html

Irregular Webcomic I check from time to time as well:

http://www.irregularwebcomic.net/

And the DFC has to get an honorable mention, although it's in a slightly different category.

http://dfc.furr.org/index.html