User Interface and Add-ons

One of my favorite features of WoW is the ability to modify the user interface via addons. I am constantly looking for ways to improve my setup. This is my current setup, which is probably about to change since patch 4.3 goes live tomorrow and is sure to break everything.

1 & 2 are hidden mouse-over action bars, 1.) micro menu  2.) mounts and hearth stone

I have quite a bit of empty action bar slots, but I like having distinct groupings so I can easily find what I am looking for in the heat of the moment. I have a big chunk of empty space to the right of my action bars that I am still tinkering with, I would gladly accept any suggestions.

Current list of addons:

Bartender, Xperl, Recount, Needtoknow, Tiptac, Playerscore, Sexymap, Addon Control Panel, Chatter, Macrobank, Bagnon, Quartz, Perform AV Enabler, Rating Buster, Reforgenator, Tidy Plates, Threat Plates, Sell Junk, Deadly Boss Mobs, Healers Have To Die, and Arena Unit Frames.