Diamond Age was fantastic. One of my favorite steampunk books is China Miellville's The Scar, which involves a floating pirate city. Say it with me. Floating. Pirate. City. Eee! Love that book.
Has anyone read Katie McCallister's Steamed? I haven't yet, but one of my friends raves about it. It's apparently a steampunk romance novel.
I read it. Sex and Steampunk and Funny. And Pirates. Entertaining!
My to read list is getting longer and longer.....
The Clockwork Dark series is a good younger reader's steampunky series, first book is The Nine Pound Hammer. Scott Westerfield's Leviathan has been mentioned, it's good. Sequel just released, Behemoth, haven't read it. I'll add some more to the list later!
But heck, almost anything can be steampunk. Think of the Wizard of Oz series. The Tin Man is so an automaton. And what was the name of the mechanical character that had to be wound up with a key? And wouldn't an Old West/Steampunk crossover be awesome?
Yes, I'm so signing up. When I have a spare minute.