Which carrier phone do I buy??

[luxuri]

Currently studying here in the US with AT&T as my carrier, however I also want to use it when I'm back in Hong Kong during holidays. Which carrier do I get so that I can use it with AT&T here and also in HK?

thanks

 

[jetlagged]

It doesn't matter which carrier you go by. Once the iphone gets unlocked, you can use it anywhere in the world.