They've already had my fav Venom in part 3 (which could've made it so much better). Hobgoblin is too much like the Green Goblin, that works in the comics but not on screen I think.
Looking at other classic villains:
-Vulture's just not interesting enough for the big screen I think.
-Scorpion might be a good one. Superhuman power, a powerfull suit and a complete psycho. Yep works for me.
-Lizard is surely a contender as the character of dr. Curt Connors was already introduced. But probably as a secondary challenge for Spidey.
-Mysterio might be funny and will give the visual effects guys quite some room to play with.
-Kraven the Hunter might also be a bit boring for a movie but could make it a bit thriller like.

I'd say Scorpion with the Lizard as secondary villain but not working together. Just to have two enemies (you can only have just 1 in the first movie).
Or with a few introductary battles in the beginning we could have the Sinister Six.
A group of villains can easily give you enough writing material.

Please, please, please Sam Raimi, can you kill off Mary-bloomin'-Jane?!!

Every Spiderman film so far has been ruined by Kirsten Dunst screaming and, on a more practical level, imagine how many people Spiderman could help if he wasn't wasting his time repeatedly rescuing the damn woman.

There is always carnage I don't see why not since a little bit of the vemon is still alive

Dylan Baker would make a piss poor movie villain. I've seen him try and he isn't all that evil (or interesting). I hope they don't do The Lizard, although one would argue that once he becomes The Lizard we won't really see much more of Baker (that's kinda speculating on my part seeing as I don't even know who The Lizard is but I'm assuming it's a big f'n lizard).

carnage should be in the next one, and somehow add vemon in as well and both should take on spiderman they have to do it would take the spiderman franchise to the next level.

The people working on this new Spider-Man movie really better step up their game, especially with the writing, after recent successful adaptations like The Dark Knight and Iron Man. After seeing those two movies, and re-watching the Spider-Man movies, it is difficult to get through them without classifying them as cheesy.

@Chris: They aren't cheesy. They just use a more classic movie formula of good fun than many of these modern adaptations, and thats just not acceptable to many of todays desensitized, uptight patrons. That isn't to say you have to like this particular series, but most any comic movie today that doesn't come with an edge of some sort, will be psssh'd by fanboys and jaded folks. Batman( '89 ), is a comic book movie with a comic book formula, whereas Dark Knight is a crime thriller movie with a crime thriller graphic novel formula. I liked both, but they're really not comparable. Spiderman doesn't take itself too seriously, and thats rare and refreshing these days. Anyway, you really don't need to "classify…" movies while watching them, unless your writing a review for r.o.s., just loosen up and ENJOY them!

I am psyched for a Lizard-Spidey showdown. I think Morbious would be interesting, but I would like Dr. Ock to return in some fashion. I do not believe that he was killed in Spidey 2. I also would not mind Hobgoblin to make an appearance.

They can't do the Hobgoblin though. Harry was the Hobgob… He's kinda dead… It poses problems…