Betty Ross

BFF: Hulk

Played by: Jennifer Connelly, above; Liv Tyler.

Relationship: Science buddies turned forbidden lovers; she was present at the accident that mutated him into the Hulk; in the 2003 Ang Lee version, she dumps him for being emotionally distant, then feels guilty; in the 2008 film, he injures her in his initial transformations.

Hurdles to romance: As in the Marvel comic, Betty's father, General Ross, is Bruce Banner's main foe; in the Ang Lee film, the General and Banner's father were deadly rivals; in the 2008 version, Betty is a cell biologist who moved on after Bruce skipped town.

Integral to plotline? Not really. Connelly, who brings as much seriousness to the role as we expect, has a more complex Betty. But she's a sounding board, not a fully realized individual. Tyler, who provides a sweet but almost vaporous presence, exists to answer our most pressing Hulk question: Can Banner and Betty have sex? (Nope. The Hulk gets way too excited.)