Haven't seen an exclusive webcomic thread, so I'm making one. Place the titles of your choice here and before anyone gets smart, most webcomics sell collected books of their work, so yes, they actually belong here.
At any rate, my picks are:
www.gunnerkrigg.com
This comic is great! Figures of folklore and mythology, radically advanced(?) robots, secrets and mystery, all set in a boarding school! I remember Neil Gaiman giving this a positive nod but I won't put money on it.
http://www.bigheadpress.com/lamuse
If you thought you knew what superheroes could do before, read this! Alan Moore likes it, and the title heroine goes sround saving and changing the world and to hell with what the establishment has to say about it. An online graphic novel really.
www.faans.com
If you are a scifi, anime, comic book, or any other variety of geek you must read this. No endorsements from comic book writers, but this one is just plain fun. And can get kind of heavy emotionally when you don't expect it.
www.somethingpositive.net
Sarcasm, jelly cats, geekdom, politics, and more sarcasm. The characters of this comic alone make this worth reading. If you read this comic and don't like it, I hate you.
www.sisterclaire.com
A pregnant nun. Junko Mizuno style. For a relatively new comic, that's all you need to know.
http://rosalarian.com/yume/
A touching series about two young women finding each other, with a twist at the end of the first half.
http://www.menagea3.net/
Nudity and sex joke warning. A blonde, tall, built french canadian female. A fun loving punk band girl. And the lucky little geek man-boy that they move in with. Not high art, but still entertaining.
Hopefully these will get people to participate with a few of their favorites.