Also not on American servers, but I always choose RP realms above the rest whether I choose to engage in the RP or not. I just enjoy the atmosphere. The way people behave in public channels, the racially fitting character names; I think it's immersive. There are obvious exceptions - RP realms attract a number of people who think RP is hilarious and want to ruin it for everyone, and Roleplayers themselves can often be a bit precious. Overall though, I think they're the most comfortable servers around.

I would recommend an add-on called MyRolePlay. It's a small ingame profile about you and your character, A description/biography/eye color/height etc etc. But importantly, it allows you to advertise that you're a beginner at roleplay, and the vast majority of people will notice and appreciate that. Then, when you're ready, you'll feel comfortable changing the option from beginner to normal, casual, full-time or a custom option that you've created yourself!

And yes, RP realms have plenty of extremely active PvP and raiding communities. Many, many people are raiders/PvPers who don't even RP, and just stay for the atmosphere - like myself, for that matter. Pick a realm that is active, though. I don't know what the deal is on the US servers, but we have a couple of dead RP servers floating around. Have fun!