Maybe they're going to do a Hobgoblin/Green Goblin thing. They could fool a lot of the fans by teasing Hobgoblin as the main villian, just to have him as a "copycat criminal" zipping around for a little while in the movie until Harry shows up in the Green Goblin costume and gets rid of him, before moving on to the main event with Spider-Man.
I hope it's not Sandman, that seems like a pretty weak alternative when they have several more interesting characters they could go to before him.
And this bit is from nearly a decade ago, but I remember Marvel was all hung up on doing a Venom movie independent of the Spider-Man films...of course, this was from back when the Spider-Man movie was still tied up in legal problems that prevented it from being made, so I'm sure a lot of plans have changed since then. I don't think Venom has enough support from comic fans, nor the recognition factor from the general public at this point to carry an entire movie.
You came back! Well, I hope I don't disappoint. Here are the changes since we posted this list last week. NEW ADDS FOR THE WEEK OF 4/6 The Last Truck: Closing of a GM Plant (The W at Amazon) (HBO, 2009) Documentary Crustacean (2009) (4/9)