Only yesterday I discovered the amazing webcomic Questionable Content. I don't know where I've been that I've missed the superior wit of Jeph Jacques, but it's worth a read for just about anyone. He's got over 1700 strips there, and I've read through the first ~900 in the past two days. Yes, it's that good. I've literally LOLed, which has led to Ann giving me several strange looks. But it's well worth it.
I figured I'd post a short list of my favorite webcomics -- I encourage everyone to check them out!