But it HAS to be the Green Goblin 2 (harry)...
Otherwise the last scenes of Spider-Man 2 would be completely senseless...
They have a storyline through the two movies and made the end of part 2 look like the storyline will be continued in part 3, so I think they'll go on with this... But nonetheless they should show us a new villain, and hopefully he'll be as great as Ock and GG (which both were two of the best super hero villains I've seen in any super hero movies.... I don't remember many others that reached their level, maybe the Joker, resulting from Nicholsons great acting skills)