Tanya Huff's Blood Books, and the spin-off Smoke Books. One of the major characters of both series is a bisexual vampire named Henry Fitzroy. (The only other character present in both series is a gay guy named Tony Foster. He's a minor character in the Blood Books and the protagonist of the Smoke Books.) Not only is the cast sexually diverse, but the books are written very well. I'm am aspiring author, and I'm amazed by her writing. Especially her character development. She really gets into what it would be like to be a vampire, or a werewolf, or a mummy who's just escaped his tomb... she makes them full and distinct characters, without making them act like regular humans. I definitely recommend this series.
If you're into fantasy (which I totally am!), then I recommend Dead Witch Walking by Kim Harrison (which is officially one of my most favourite books) to you... Though I should mention a couple of things first: 1. The main character Rachel isn't/doesn't start off as out-right bi... I haven't quite read all of the books in the series up to the point where she gets to being bi, but I do know that it happens (as I've got one of the books on my bookshelf... I like reading things in order, so I've stashed it away until I'm ready to read it). 2. Even though the books are a "series", they aren't actually under any series name or advertised in any particular order... but I'll post a link a link here, just in case you are interested. Order of Kim Harrison's Hollows Series (Oops, I guess it finally has gotten a series name: the Hollows! ) I hope this helps!
