MmmmmmmmThat is one of the biggest things that turns me onto a guy, believe it or not. A non-US accent is sooooooo sexy to me, for some reason. I drool when I hear people like Alan Rickman or Colin Firth talk, mainly because of their voices (ok, maybe there's a little more with Colin Firth, but you get what I'm saying.)
The absolute hottest guy I've ever liked was from Poland, my senior year in high school. He was a brilliant student with a sexy body, but the main thing was his accent. His English was flawless. I never heard him make a mistake the entire time I was his friend. However, he still spoke it with that rough, sexy accent that he was raised on.
Now don't get me wrong: there are plenty of other factors that go into thinking a guy is hot. If the guy has an accent but dresses like a gangster and uses intentionally bad grammar (My grammar is not perfect, but dammit if I don't try), I'm not going to find it sexy at all.
It reminds me of that scene in 'A Fish Called Wanda', where John Cleese is dancing around naked in the apartment shouting foreign words to Jamie Lee Curtis. You know what I mean.