In an interview with Dark Horizons Sam Raimi talked about a possible Spiderman 4:
"Question: I want to apologize for asking the Spiderman 4 question, but what would it take to bring you back for a 4th film? You've said great story, obviously. But it feels like this 3rd film really wraps it up, a nice neat trilogy, so what would it take to bring you back?
Raimi: Well, we really did try and wrap up a lot of the story elements that we had in the first and second picture, but I look at it more like the end of a chapter, because if you've read the Spiderman comic books, you know there's so many more villains and so many more stories that can be told, that have already been told, that are very exciting and vivid, but it's true. I, for me to come back, I'd have to, when I'm done with all of this, have a breather and then look at the character and say where does he next have to grow to? Where can he now develop in a meaningful way? And if I could recognize, honestly, a real deficit that he, and we could fashion a story then where the characters, where this young man could learn his next life lesson in a meaningful way, and that we could make good story out of it, then I would die to direct the picture."
"Question: Is there a release date for Spiderman 4?
Raimi: They haven't told me.
Question: If you were to sign on to do another Spiderman 4 film, or even possible few films, with the pressure you were under to deliver 3 by a certain date, would you be more firm with the next one? I want this to be--everything more set up in advance?
Raimi: No, because the fans, I mean, that's really, that's a Sony decision. I'd have to ask myself can I get it together, the body picture I need in--
Question: If they he [Tobey] said no to a fourth film, would you be more reticent to do Spiderman 4?
Raimi: For me, yeah, because I've made all these three with him, he's like my partner, and part of it for me would be a real specific experience of continuing the depth of that character that he portrayed. It would be another story working with someone else on the character.
Question: What about Kirsten?
Raimi: I love Kirsten, she's great, but what about her?
Question: Same thing. If she said no?
Raimi: It would be very difficult without her also."