I think every girl should own one push-up bra, that's my personal rule of thumb haha. I like underwire bra's, that is a must no matter what. I also like fun prints and lace. Lace bras make me feel sexy under my clothes even if I'm the only one who knows. VS Tee shirt bra's are awesome. I don't like the super plunge bra because that's just taking the whole push up thing too far. Most of all, I like bras that fit! Nothing is worse than a girl wearing a bra (or lack there of) that does not fit. Foundation is everything, and makes a huge impression!
Well, I need an underwire, so I always have that. Unless it's a sports bra, then it just needs to be tight enough to keep those suckers out of the way. Anyway, I don't have the money for fun bras, so they're usually just your generic nude, or black. I have a really weird bra size too, so I don't usually have a whole lot of options.
I hate wearing bra's but I like the lacy, or fun print solid cup kind, the ones with the loose fabric for cups creep me out, but I don't really get any cute or sexy styles in my size which is a bummer =(