Once in a while, I read a book that completely blows me away. Sometimes it's science fiction--Cyteen and Downbelow Station by CS Cheryth did. Sometimes it's romance--I still remember the first Jennifer Cruise Harlequin Temptation I read and thinking--this is what category romance can do. Sometimes it's mystery--Elmore Leonard or T. Jefferson Parker can write a mean line. But most often, it's fantasy.
I think the reason is that fantasy opens all possibilities. Authors can write a fantasy so funny it'll knock your socks off--if you haven't read the Thursday Next series by Jasper Fforde, you've got a treat coming. Sometimes fantasy lets us look at our own world through different lenses, seeing what we should have known--Harry Turtledove does this in his fantasy alternate history tales. Sometimes it opens new doors--when I read Lord of Light by Roger Zelazny for the first time, I hurried to the library to research Indian religion. Sometimes it makes you cry--as George R. R. Martin's A Game of Thrones did. Sometimes it's just plain fun.
I've read lately that paranormal romance is on the way out. I don't know--my paranormal romances (One Handsome Devil and In the Werewolf's Den) seem to sell better than most of my other books, but that seems to be what I'm hearing from New York. I don't know if that's true although certainly not everything the New York publishers have put out lately has been as good as it might be, and I have to say that I could go a long time without another hunky immortal vampire. I hope, though, that fantasy will always be a major part of what's published, and that publishers will continue to seek new, creative, and wonderfully powerful fantasies like the ones that first inspired me to want to write.