An update on the Gandara server. It is sometimes showing as full, I think because of recent successes in WvW. If you want to join Shi and me who have toons there, keep trying. It fluctuates depending on time of day and you'll get a chance to create on there if you keep trying. I would say it's probably worth it, seems a nice server. Once you've managed to roll your first toon on a server it becomes your home worldand you don't need to worry about it being full or not for logging in and subsequent toon, you can always log in. However if the zone you are playing in is too full you can get placed into overflow.
Overflow is a temporary server. This means you can play the game and do quests while you queue to join your home world. The only thing you can't do from an overflow server is join WvW. Overflow servers are made up of people from all servers and languages, so if you're seeing more French or German than you expected, this will be why. It's a nice system because it means you can play while you queue and once a slot in your home world becomes free you move there (if you wish, you can choose not to if mid quest).
Note: there's no overflow for capital cities. So if you log out in your capital you'll always log into your home world (but might have to go via overflow if you zone to a quest zone).