you do probably still want to stay near the US as it has more density of interesting tech people than any other country (not at all slighting UK, Singapore, Aus as I have met great peeps in all of them). Better to be within 2-6 hr flight of any interesting tech hub than to pick specifically one city since most cities have something to recommend them.
I see some folks recommending SF/NYC, but having done both, i would also say its possible to overdo them. 1-2 weeks of them every 3-6 months is plenty. if youre based in miami, people are generally happy to come visit you :)