Spider-Man 4

Will there be a Spider-Man 4? Or was this destined to just be a trilogy?

The way they tried to cram everything into S3 could mean they wanted to get all the storylines wrapped up and Spidey capped while they turn their attention to The Avengers. X Men were done as a trilogy. (Although, Wolverine's pre-story was aching to be told.)

So who would be the Big Bad in S4 if it ever happens?

Mysterio is an obvious one. His real name is Quentin Beck, who was cameoed in S3 by Bruce Campbell. You know Raimi would love to use Campbell in a major role, so perhaps he's been saving him for S4?

There is also The Lizard. Curt Connors was name checked in S1 and appeared in S3, so that's a possibility.

There's always The Vulture and Kraven The Hunter. Or even Electro.

Or, if Marvel want to bung in as many villains as they can for a Spidey film, bring in The Sinister Six, which includes Kraven, Electro, Vulture and Mysterio, and will bring about the re-appearance of Doc Ock and The Sandman.