Regarding being hooked up based on music preference:
It's a requirement that my girlfriend A) is an attractive girl containing all the necessary attractive girl parts..
B) Doesn't horde them.
But, to be in a relationship, long-term, it's a requirement that I'm able to stand being around her. So personality is a big factor, but I also don't want to come home and have to endure music I hate and listen to her talk about it, nor would I want her to have to deal with the same. Stuff like that tends to erode a relationship little by little until all that's left is a gaping maw of a life drilled silly by Jay-Z or Ashley Simpson.
Fortunately, though, I have a way around that.
- Don't join relationship.
Listen to what you want... just not while we're having a one-night stand.