I have to admit, there's something about Seam that intrigues me. Maybe it's because they put up a really nice-looking demo (I'm a sucker for eye-candy), or maybe it's because it seems to be well documentated, or maybe it's the fact that it's based on J2EE standard technologies (EJB3 and JSF). It could also be that I greatly respect the work of Gavin King (who's always been respectful to me when I asked Hibernate questions back in the day).
It could be the lack of configuration, but I think it's the simplicity that gets me. A POJO (Entity Bean), a Session Bean for your business logic, and a view page (w/ Facelets no less, which is very cool). Other new frameworks this year include Wicket and Stripes. While these frameworks look cool, I really like the idea of a full-stack framework much better (I do use AppFuse after all). Well done Gavin - Seam looks very cool IMO.
On a related note, I upgraded AppFuse to MyFaces 1.1.0 yesterday w/ minimal effort. You can grab the latest from CVS if you'd like to get started with MyFaces quickly.