Comics already mentioned aside, I'm a big fan of MS Paint Masterpieces. It's like a sprite comic, but good. Only problem is it updates for a few comics, goes dead for a few months, and then updates again.
Several friends from back in the day tried to get me into it. "It gets better," they would always tell me, but I am not slogging through something going at a snail's pace. Sometimes stories take a time for the plot to start and sometimes they really do get better, but this was ridiculous and boring. I didn't get very far.A few years ago I used to follow a bunch of web comics, most notably Homestuck until I realized it was a pile of shit.
I just love how the artist can change styles on a dime and do them all well. Like this one (linked due to length).Perry Bible Fellowship.
Prove it isn't the best webcomic ever.
It doesn't have shit to prove, though.