Well the weird thing is that Guild Wars 2 apparently has a datacenter in Texas that you connect to as US, and then after that you can choose between US Server Center or EU Server Center. So not sure what the pings are going to be like, best bet is to wait till Saturday and see first hand.
If servers are the downfall of playability for a such a awesome looking game, I'll be quite upset. Test results are around 248-249ms so somewhat playable considering original server I was on in Star Wars had this.
Oh yeah, from Reddit:
The US servers are in Texas. The authentication servers are also in Texas, so the EU folks go there for logging in but play on their EU servers.
Really hope that it will be playable. 250ms is about the absolute best ping that aussies can hope for connecting to Texas.
Keep in mind that 250ms will roughly increase your reaction time by x3 compared with someone <100. I used to play competitive FPS and 250 would render even the best players non competitive.
Hopefully GW2 is more forgiving.