I've got a rather deep voice despite my slim appearance, it makes me sound older than I am - I'm starting to reach the point where my voice somewhat suits my age.
Other than that, I'm actually foreign to English, but I speak it more or less fluently, so I sometimes have to convince people, that I've never been to the States or any country where the primary language is English, let alone lived there. When I got my grade at my oral English exam, I was asked how long I had lived in the States by the censor, I was amused by that.
Even though I'm Danish, I don't speak with that horrible hot-potato-in-the-mouth accent, I honestly don't think that my voice gives away my nationality/origin. One of my fellow gamers, back when I was addicted to WoW, claimed that she'd have her way with my voice if my voice was a person. Flattering, but creepy. x3