Thanks everyone for the recommendations.
Though I may have gleaned some ideas from this thread so far, I'm not sure how many (if any) of the recommendations I'll actually check out.
(quote and comment deleted, since it broke the spoiler farther down).
I'm reading The Eyre Affair by Jasper Fforde now, and it has its cute parts and some creative wit, but I can't really call it "funny" by my definition. None of the Discworld novels I've read so far are especially funny, though I do enjoy reading them still. "Another Fine Myth" by Asprin was enjoyable (and I hope to come across more like that--Aahz was a good character), but not really funny. The thing is, these are all in the sort of genre I am most interested in, but the humor is quite tamed in most forms.
Modern novelists offering situational irony and observational humor, especially in essays like Sedaris can be good, but I really am more into slightly more unified narratives. It's a nice, and sometimes effective style of humorist writing, but leaves me feeling empty.
I think Pratchett has a lot of good stuff in it, but the humor is fairly contained. Often since there's a lot going on with different characters, it's hard to implement a lot of silly arbitrary humor. From Christopher Moore's Lamb:
Perhaps it doesn't have a tremendous amount of subtlety, but the random craziness that crops up just keeps me laughing. It does something to interrupt the linear narrative for a laugh without completely derailing it.
I better keep looking. I hope people keep contributing to this thread. It'd be great to see why
you find something humorous, rather than the fact you find it humorous. Since we won't all laugh at the same things, it's nice to know what the recommendations come from.
Thanks again everyone!