Were Geek - http://www.weregeek.com
Sinfest - http://www.sinfest.net
Order Of the Stick - http://www.giantitp.com/comics/oots.html
xkcd - http://www.xkcd.com
Goblins Comic - http://goblinscomic.com
Girl Genius - http://www.girlgeniusonline.com/comic.php