Fevre Dream
If you can find this book, it is an excellent read. Its about vampires and riverboats on the Mississipi. I think it is one of his best works. G.R.R. Martin was the editor of the Wild Cards series, and wrote some of the stories for it. That is a series about superheroes in a "realistic" setting. Some of it is very good (especially the first book, which creates an alternate history from the 50s to the 80s), though as the series continued it got bogged down. His new series, a Song of Fire and Ice, is a fantasy setting that starts off very promising; the first book A Game of Thrones, was one of the best fantasy books I've read. However, in my opinion, the quality of the second book fell drastically; I'm sure many people will disagree, as it is a very popular series. I haven't read the third book, so I can't comment any further.