First of all, we can probably come up with some general advice and observations about the advantages of RP-PvP realms. When it comes to world PvP, realms packed with roleplayers who want to stretch and fill the outlines of Azeroth's factional war probably see a little more organized action than others. If you play on an RP-PvP realm, would you agree this is true for your realm?
I want to know what the most dangerous PvP realms are. I leveled my original main (I've since switched to a RP realm) on a PvP realm, as well as dozens of alts, and didn't find a challenge there at all (Nerzhul - US). So when people talk about the danger of running a toon on a PvP realm, I have on idea what they are talking about.
Let's see if we can't come up with some sort of consensus on the most active and dangerous PvP realms in WoW right now. This is an opportunity to help out fellow players with specific realms recommendations and cautions -- it's time to name names! Where's the hot world PvP action? What are the dead PvP realms to avoid?