Originally Posted by Kahran Ramsus
Not counting Catwoman, who isn't really a traditional love interest in her many iterations, my favorite is Gwyneth Paltrow's Pepper Potts. Her spats with Robert Downey Jr are a highlight of the Iron Man films. They have fantastic chemistry. She's the second best character in those movies, which is really quite an achievement.
Worst is the Katie Holmes version of Rachel Dawes who is the clear weakpoint in an otherwise great film.
Pepper is my favorite as well. Kidder was good as Lois in 2 films, Atwell was awesome as Peggy Carter, Emma Stone was great as Gwen Stacy, Portman as good as Jane Foster as was Liv Tyler as Betty Ross. Hathaway as Selina Kyle was the best thing about TDKR. And Connelly was wonderful as Jenny Blake. Not sure if I can think of any more I liked. Oh, Wright was pretty good as Karen Jensen. That's about it. I treat love interests who also happen to be superheroes in their own right as a separate category, so no Natasha Romanov, Jean Grey or Rogue on this list.