This is an important issue to discuss for the sake of the series' future, because as of right now I doubt that Maguire or Dunst will be back after #3. After its release next year the crew will probably face the task of finding a new Peter/Spidey and MJ.
Yes, Jake Gyllenhaal seems like the most logical choice for the next webslinger as people have said. I wonder how Dunst would react to it, considering her on-again, off-again affair with him. Maybe this could finally be the time for Gyllenhaal to enter the superhero world, after his failed attempts to land the Superman and Batman roles. Another good choice would be Colin Hanks.
They shouldn't kill off MJ in #3. She's basically the Lois Lane of the SM franchise, if you know what I mean. I would like to see a natural redhead play her sometime, but unfortunately there aren't too many of 'em in the right age group (at least in Hollywood right now). Even though Allyson Hannigan was in Buffy, people still know her from American Pie as the band dork, which MJ is the opposite of. Bryce Dallas Howard would have been great, but as most of you all know she is already Gwen Stacy. In reference to another thread, Lindsay Lohan is so much like the character in a few ways (the hot redhead guys can only dream of, NY upbringing). However, she's still pretty young and doesn't seem to like her red hair very much, judging from the way she's treated it lately.