For Stephenson, try Zodiac. It has some great humor although it’s a contemporary story, not SF. Though Snow Crash is the better known of his earlier novels, it really peters out towards the end. I tend to find his work a real mixed bag.
If you like Fantasy, I’d like to recommend Daughter of the Forest by Juliet Marillier, its an expansion/retelling of the Irish fairy tale of the 7 Swans. I forced my old reading group to read it (practically under gunpoint) but they all ended up loving it. It just has good writing.
I also really like Jasper Fforde. Especialy if you have a literary background or have read a lot of Classic English Literature. Even if you haven’t though.
For nutty/wierd/out-there, Cory Doctorow is your man. You can read his story “Craphound” online and decide if his style appeals to you. He has two novels: Down and Out in the Magic Kingdom, about a far future world where Disneyland is run by volunteers who permanently inhabit the exhibits and the only currency is what other people think of you. Eastern Standard Tribe, which I haven’t read but apparently is about a future time when people ally themselves into tribes based on their timezone.
BTW, I thought Hominids started strong, but the second two volumes were big disapointments. If you’re not into heavy handed moralizing, steer clear of Humans and Hybrids. A shame really, he had a good concept and the first book is really enjoyable.
Izzybella sorry you had to encounter Robert Jordan and it put you off the whole genre. There are many who count themselves rabid SF/Fantasy fans yet loathe him with the burning passion of a thousand fiery suns. I’d hardly call him the best of what the genre has to offer, his latest books have underwhelmed nearly everyone.
Not SF, but wildly funny and highly recommended, is Headlong by Michael Frayn (you might know him as the author of the play “Noises Off” which was made into a movie of the same name). It was shortlisted for the Booker Prize a few years back. Its about a guy who’s trying to finish his PhD when he notices what he thinks is a lost painting by Breugel blocking the draft from his neighbors’ chimney. Madcap adventures in art history and/or art theft ensue.