Scottish and Irish are equal-opportunity tasty accents. The hotness of straight up British is inversely proportional to how pretentious you actually are. I'd also like to give a shout-out to Italian and Spanish (as in, from Spain) - yum. However, I'm not that big on the French accent, as it mostly sounds like your mouth is full of marbles (although actually *speaking* in French? is dead sexy).

Australian: hot in men, incredibly obnoxious in women. After living in a dorm in Queensland, I decided that most Aussie girls sound like they're whining no matter what they're actually saying. New Zealand, OTOH, is just weird - it's like British English on LSD.