I have read online that Sifo Dyas is yet another Sith lord. I don't know if this is true, but I agree that this was the most ridiculous plot hole in the movie.
As for expanded universe stuff, I am not as satisfied as Nick is with it. I think some of it is very weak (Dark Empire, Shadows of the empire), but there is some that is very good (the aforementioned Timothy Zhan novels, the Courtship of Princess Leia).
As for me, I will probably stay away from most of the expanded universe stuff (unless someone recommends it).
Edited to say I forgot to mention that I did enjoy the "Clones Wars" cartoons (Cartoon Network) immensely. I recommend them highly.
As for Schrodinger's cat, I think it would more clever to have a cat named "wave equation."
