Well as always the "What class should I roll?" question can only be answered by yourself, especially in an RP environment.
You are of course limited by the ingame character classes. I for one can't really stand leveling a class a second time, but one might say roleplaying a class you know game-wise might be easier. Hard to say.
The question which server to roll on has been asked over and over in the RP-Forums, I would suggest using the search function.
Only you know for sure what'll be right for you. Make a character first.. Don't worry so much about the race and class until you know exactly what you're gonna do.
I suggest trying out the RP forums here, too. A lot more room for creativity here. People usually look at you funny if you try to do something actually creative ingame; they adhere very strictly to the actual game mechanics rather than how RP goes naturally.
As said, check the forums, that's been asked many times about what server is best. I personally do not roleplay ingame so I can't say personally.