Balmung? Seriously, Balmung is pretty much the player-community designated role-play server - as a result though it is almost permanently locked to new character creation due to being massively overpopulated, although you should be able transfer your character there from another server (I managed to transfer there from Ridill myself without any problems).

I've heard there are much smaller RP communities on other servers, but Balmung is the place to go for RP.