Diablo III gets ever closer to release, you've probably moved on from the question of what you're going to play and on to the question of who you're going to play with. If your friends live across the planet, that's going to make things a little more difficult, but with the new Global Play feature, not impossible. Players will be able to play in any region, although the real-money auction house will only be accessible in your home region and your characters from the home region won't transfer to the global service.
You hadn't forgotten the real-money auction house, had you? Just in case you had, a new official guide is available detailing how the service will work, what regions can use what money, and of course the actual mechanics of buying and selling. Players using the global play feature will not have access to the real money house of other regions, but will have access to the regular auction house, so even if you're planning on a global jaunt, it's worth examining the particulars.