I have heard different things about being able to transfer to a locked server. Can you really transfer on when it is locked to character creation? That would be great, as it was a pain making alts to check out some more crowded servers. xD

More on-topic, if I was looking for a high pop NA server I would pick Gilgamesh or Excalibur, or possibly Leviathan or Behemoth. Best of luck with your choice!