Kaoru fighting. I think Kaoru is a very cool character. She's just as willing as Kenshin is to fight for what she believes is right, or to protect the ones she loves. It's true that she's not anywhere near as strong as Kenshin or the other characters who fought during the Bakumatsu. However, that's OK, since she is a character of the Meiji era, and is certainly strong enough to deal with the sort of petty thugs prevalent during a time when it was illegal to carry a sword.
I just wish the show's creators would give her more chances to use her Kamiya Kasshin Ryu.