I can't wait till they start doing stories from the Silmarillion, which (let's be honest), is all but inevitable if they get a substantial profit from this. There's some epic battles in there that would be really well-suited to the style these movies seem to be being made in, which isn't a style I think suits the Hobbit very well. If they keep up the trilogy trend, I'd expect to see Beren and Luthien, Turin, and the fall of Gondolin, but maybe they'd try to milk the cash cow even more and do a more complete rendering (although in this case you'll wind up with all sorts of moments that aren't well-suited to the style).
Less tangentially, I'm hopeful. I think you could do a trilogy very well, but you'd have to refrain from the Epic style of LotR for the first one (up to Gandalf's departure), go back to it during the second (The Offscreen Adventures of Gandalf), and then blend the two for the third (the rest of The Hobbit). However, I think there's a good chance it will be an excellent movie on its own merits and I expect I'll enjoy it for that, even if I don't think the tone is going to be a good match for the Hobbit. I would absolutely love to be surprised, though.