if you live in the USA and like PVP, but aren't huge into RP....
Er... there's nothing about RP servers that requires RP. You can play on an RP/RP-PvP server without being "huge into RP". They are just labeled so people who like RP can have an easier time gathering. I haven't RPed a minute in my life, but I play on Ebon Hawk (RP) and Jung Ma (RP-PvP). I'd say that only 10% (or less) of the players on the server are RPing at any particular time.
The RP-tagged servers generally have more mature players (especially comparing Jung Ma with Prophecy of the Five) and generally more supportive communities. There is generally fewer jerks around and people are generally more understanding and willing to help each other. And the populations aren't hurting either: Ebon Hawk actually seems to be one of the most consistently busy East Coast servers. Also, there is generally much better balance between factions on the RP servers.