i voted ass...another thing thats a big turnon or turn off is teeth, if a girl has a nice set of teeth shes hotter, but if she has screwed up jumbled crap its a big big turnoff. tits arent as big a deal with me, but the 2 girls im currently talking to/ might get with during summer are like 34D and 32C so...cant complain
i'd like to say tits, but honestly, a girl can have a nice rack but still have a nasty flat ass.. i prefer a nice sculpted bottom with nice legs. tits are tits really, they sort of 'come with the package' where as an ass and legs are two for one deal. but to me a hot girl contains all of the above obviously.
edit: oh yeah, unless the tits are anything special, i wouldnt worry about it. i mean they have to be either: huge or just plain big.
it all depends on the person for me really. some girls just have a perfect stomach, and that's a big turn on. some girls have a perfect ass i just cant look away from. some girls have a perfect rack i cant get enough of
face is even a big thing for me. everytime i forget how much i like a good face, someone like this pops up and reminds me all over again