A new PvP Chloromancer / Warlock soul has been a lot of fun for me lately.
It's a simple idea, just go Chloro main and drop leftovers in Warlock for the instant-casts. You turn into a little ball of life damage and healing, rolling around the battlefield.
Chloromancer (36) / Warlock (12)
The best part of this build is that it is incredibly mobile. You have 6 instant abilities you want to hit every cooldown, and then you have Opportunity procs handing out more instant casts. I have never really played a Soul this mobile before, and it is wonderful. As a Dom or Chloro/Dom I felt picked on as rogues or warriors would just walk up to me and shut me down from really getting any spells off.