This was posted a while ago;
It shows a comparison of D3 (updated server:client infrastructure) to D2 (quite old as we all know). You can see that the delay he has as an Australian no longer exists when he plays D3. I know a lot of people have worried about this, so here you go. This is, of course, of particular interest to those people who are too scared to play hardcore simply because of their internet speed.
Of course, random DCs might still kill you, but hey, what's life without taking risks, yeah?