I'm definitely gonna go see it. I have my own imagined version of Middle Earth that won't be ruined if the movie doesn't measure up. Jackson's vision in LOTR was so close to my own, it surprised me. I have to give THE HOBBIT a chance.
If it is done well, I don't see a problem stretching it to two movies. There is a lot of detail in THE HOBBIT, just not as much large-scale violent action. Maybe that makes it less of a big crowd pleaser... but if it's well done, it will live on for years among Tolkein fans.