It really doesn't matter, but I do like long hair. It's nice when it's wavy too :P and soft. But it really won't matter in the end. Don't know if I'd say long is necessarily as long as boobs length, but whatever lol.
I prefer longer hair pretty much always, but shoulder length is okay. Only a small number of girls can really pull off hair shorter than that and look good, and they still rarely look better that way than with longer hair.