It's being reported all over the place (although at this time it's strictly rumour) that Spiderman 3 will not have one or two, but four villains.
The word is that the villains will be: Sandman, Hobgoblin, Vulture and Venom.
Personally, I think this is a load of B.S. as the latter three have a very deep history in the Spiderman mythos. I can see perhaps having one villain along with Sandman, who I think has always been a bit of a second-rate bad guy, but it would be awful if they tried to cram Hobgoblin, Vulture and Venom storylines into one film. It would do none of them justice and would dilute their characters.
This is probably just internet-rumour-mongering at it's best. If it's not a rumour, it's a really bad idea IMHO.