X-Men 1 and 2 are strong but X3 is pretty mediocre. Spider-Man 1 and 2 are good, but 3 is awful. Star Wars...I really only think I can bring myself to rewatch Ep3 at this point.
So for now I'll go with X-Men. Its weakest link (X3) is the strongest of the three week links in all three of these chains (Ep1, Spider-Man 3).