Oh man. I've been steadily keeping up with Gunnerkrigg Court (Please read this comic it's so good), Flaky Pastry, Manly Guys Doing Manly Things, and occasionally Awkward Zombie. I've read Paranatural, and while it wasn't so much for me, it is one of the best webcomics I've ever read, with just amazing dialogue and a great plot, and it's the only webcomic I've ever read that actually made me laugh in person. I've read Ruby Quest and Nan Quest (though Nan Quest hasn't been finished and I don't think it ever will be), Problem Sleuth which is good, followed League of Super Redundant Heroes for a while but realized it's a little lackluster, and kept up with Ava's Demon until it fell into the hiatus pit for a while. I think it's been revived though, which is great because it's gorgeous and interesting.
Above all these though, if you're into webcomics in general, the Bad Webcomics Wiki is good for a laugh. They document all sorts of webcomics, popular to obscure, that they think makes the cut for a bad webcomic and write lengthy critiques. A lot of the articles are well-written and researched, and actually very fair--they don't just rag on hobbyist's comics with no regard for the effort it takes to make a comic, and in fact offer guides on how to avoid laziness and bad writing.