I think it's cool you have a unique/interesting sense of.. style? It's a fashion choice right? It's nice that you're confident enough in your sexuality to express yourself in a way that's traditionally for females :D
oh and no it's not a turn off, as long as you're not the type who talks incessantly talks about the importance of getting a mani/pedi once every two weeks (I know a straight guy like that) :P
Honestly it doesn't matter. Your nails don't define you as a person, or your sex appeal. And just think, isn't it better to have nice nails, than nasty dirty ones? For a lot of girls (myself included) guys with gross nails/hands are the turn-offs.