Check out these video interviews with Spider-Man 3 director Sam Raimi and stars Tobey Maguire (Peter Parker/Spider-Man), Thomas Haden Church (Flint Marko/Sandman), Topher Grace (Eddie Brock/Venom) and Bryce Dallas Howard (Gwen Stacy).
Raimi remarks that the first Spidey film was about things that happened to Peter, the second film found Peter making choices and the third is his turn toward the dark side of his soul.