I think that this film will definately make more than "Spider-Man 2", and has a good chance to make more than the original Spider-Man. I think this not only because Spidey's most popular villian is in the movie, but also because of its darker nature and (in my opinion, from what I've read) better story. But these aren't the only reasons I think it will do better. While some may think that having Shrek 3, POTC 3, HP5, F42, and Transformers coming out after it would be a bad thing, I think it will have the opposite effect. I think that this gives Spider-Man 3 a good chance at making a new Opening Weekend record, because people will want to see this movie in time for the other movies to open, so that they can see them too. Also, people who don't normally go to see movies will look at all of the options available and think, "Wow, with all of these great sounding movies playing, I should see one or two". And because Spider-Man is the most popular superhero movie franchise, this movie will be one that those people will choose.
At least, these are my mindless ramblings. Feel free to berate me now. yay!