I'd agree that when multiboxing, it's better to find a lively guild for all of your toons so that you can always have people to talk with while you're online. I'm in a very active guild right now with all 5 toons, and I'm enjoying every moment of it. Plus, some real life co-workers are multiboxing now, so they're also available to talk with. As far as the DPS is concerned, you've mastered your skill rotations and you're a smart player. Those two assets alone (and then gear) are your best items for topping the DPS charts :P.