The only webcomic I've ever read really regularly is Perry Bible Fellowship
, but it's finished now. I also have enjoyed most of the XKCD and Cectic comics I've read, though I haven't followed either regularly.
As for Girl Genius (mentioned in the original post), if you ever see characters by the name of Vogel, Krizsan, or Strout, that's referring to the people who made the game in my signature, below. Phil Foglio made some artwork for the Avernum series by the same company, so that's why they get cameos. I haven't read the comic myself, though I hear it's pretty good.