The hospital scene!
That scene when the doctors attempt to cut off Doc Ock's new limbs is amazing. I remember it being shocking when I saw this movie in the theater when I was 13, but damn. I just saw it again and it is so perfect. Raimi clearly took the opportunity to display his style from making the Evil Dead films here.
I can't believe this scene isn't talked about more. It's one of the scariest scenes in any superhero movie I can remember.