Living near Boston and hearing this accent spoken enough times, I can honestly say:Moonlight Butterfly said:English with a Boston accent. The accent that turns me to mush when guys have it.
Also Irish, Irish is nice too.
Why would you want such a thing?
Don't get me wrong, it's not an accent that I hate and I've caught myself dropping my "R"s a few times, but I wouldn't consider it the most refined accent in the world. Namely because in most true Boston accents I hear, every other word spoken seems to be a profanity. Although now that I think about it, just peppering everyday conversation with causal profanity would probably be very amusing.
OT: I'm just gonna be lazy and say English so I don't have to learn a new language.