Yes all the servers are go to-able as far as I know, japan just got added, not sure what is not connected yet. But anyways yes you can go to US servers on a EU CD Key, I dont think there is a difference between the CD keys at all anyways.
iirc, when I installed GW over 2 and a half years ago, I was given the option as to whether I wanted my home server to be US or EU, and I have always been able to jump into EU and INT districts.
When the game first began you were only allowed 5 or so switches between regions (US, EU, etc) but since they made trader prices universal and changed the favor system you can freely move between regions.
OK. Thanks for the clarification. I was always able to go into the INT districts, but never really had a reason to go to EU districts until the last year or so, after the Favor change.
