First of all, I've never read the Spider-Man comics, so I have no idea if the first 3 movies were good or not in terms of comic book adaptation. But I did enjoy watching them (I didn't like the 3rd one so much, though), but they were pretty campy and I really like Tobey Maguire in them. I've read some comments online that the reboot should be more faithful to the comics, and will be a bit darker and serious, ala-Dark Knight.
The new movie stars Andrew Garfield, who I only know from "The Imaginarium of Doctor Parnassus", as Peter Parker/Spider-Man and Emma Stone as Gwen Stacy. Yay, for Emma Stone! I would have watched the movie just because she's in it, but now that I've seen trailers I am definitely watching because I'm intrigued.
Whoo! Web shooters! Can't wait!