What I meant by "ball of the month club" was not a literal club, just that "itch" you're talking about. I mean getting too wrapped up in always wanting new equipment when you don't necessarily need it.
Oh, here are some more specific ideas based on your needs, even though I still think you're fine with what you have.
Dynothane:
Vendetta Black Solid (Supposedly one of the best "control" balls there is, great for medium or even medium-light conditions.)
Element Zr40 (Very new, but sounds to be another great control ball, which is something you could probably use.)
Brunswick:
Absolute Inferno (May overlap a bit with what you have, but you may like it so much you use it exclusively.)
Smokin Inferno (Nice Skid/flip ball for medium to medium-light conditions.)
Zone Classic (Classic Activator cover, a HIGHLY proven performer.)
BVP Rampage or Nemesis (I've seen people have a lot of success with these.)
Hammer:
How's about that Doom? You're a hammerhead already, right? Why fix what ain't broke?
Columbia:
Uturn Pearl (Great ball with another proven cover, excellent on Medium to medium-light.)
Track:
Slash (Another great control ball, here.)