Depends which Spider-Woman. For dark-haired Jessica Drew, I nominate Rose McGowan. Jennifer Connelly would have been perfect, but she’s getting a little too old (and too skinny). For red-headed Julia Carpenter, maybe Alicia Witt (since she didn’t get cast as Mary Jane Watson, she still has a chance to be a hot redhead in a Marvel Spider-based franchise).
There really is no point discussing it. Past experience has show that if they do make the movie, they will follow the pattern of past comic female roles, and cast whichever flavor of the month actress they can get. Whether she is suited to the role or not.
Reference:
Hallie Berry as Storm
Jessica Alba as the Invisible Woman (Really, is it too much to ask that Sue Storm be the same ethnicity as her brother)
Hallie Berry as Catwoman (sort of).
Kirsten Dunst as a dishrag…,. er Mary Jane.
How about Elizabeth Banks? Smart, hot, sassy. She’s already played J. Jonah Jameson’s secretary in all three Spidey movies, so (depending upon how attached you are to Marvel canon) she could get spiderbit, too.