To help both of you, the number of chocobos next to a server name vaguely represents its current population at that moment, so that's one way to judge. In general, relatively few people play right now, but the most populated server is supposedly Selbina (because it's an FFXI reference, probably :P).
Good luck out there!
____________________________"... he called to himself a wizard, named Gallery, hoping by this means to escape the paying of the fifteen hundred crowns..." (Machen 15) "Thus opium is pleasing... on account of the agreeable delirium it produces." (Burke para.6) "I could only read so much for this paper and the syphilis poem had to go."