They're all really good, it's hard to choose, but I think I'd go with red. Also, I can't help but think of Flora, Fauna & Merryweather from Sleeping Beauty casting spells and arguing over the color. "I think red would look nice." "No, green's prettier." "No, blue!"
blue says "i'm fearsome, but i have a calm friendly side to me" still sexy though
not sure what green says to me but if i had to guess....um a casual kind of dragness
purple is saying to me "i'm here, look fine, and not afraid to show my sensitive soft side, and PROUD OF IT "
mmaahaan this is a tough one bro.......um...uh i would have to say purple, red and blue cuz they all speak to me strongly..but if your looking for a single color i would have to say purple, definitively purple