For me it's her sense of humour. She always says the funniest things, and she's got a good taste in TV/music/films.
Wow, you totally ninja'd me be like ten seconds. Way to not make the group yourself!
She's a cool person in general, and I love her humor. She can easily take a good joke, and dish one back out. Not to mention she loves ATHF.
When it comes to Pokémon, both of us seem to really feel the same way on so many things. I think it's cool we do. :)