In my case, I'm generally not a big PVPer and I play on a PVE server, so no real world PVP.
I don't know that I have the skill for arena yet, with all the CC and co-ordination required. I might give it a shot down the track though.

Before I quit WoW and came back, I used to really enjoy AV particularly (because of the PVE/PVP mix) and would like to be able to do that again. I feel like running 5 in AV, especially if it's essentially a dungeon team (ie tank, heal, dps) could make for a lot of fun, and would give you some power to really affect the outcome. Like rushing to the bosses/towers and being able to take/hold them either by yourself or with only a couple of other people helping.

Honestly, I am just having that much fun multiboxing and getting a lot of satisfaction out of it, so I want to keep trying different things!