Not 100% satisfied yet. Thinking of mucking about with a buff mod and might add some panel behind the chat/combat log.
Spent ages looking for a Vertical HUD - found that I've gotten used to it so much that I muck up horridly without (most noticeable on my Rogue with regard to energy restraints). Just really disliked the rest of the HUDs.
There's 2 bars hidden on the right side which show on MouseOver. Mostly contain silly stuff like the Mount, Water, Travelform Macro, professions etc etc. There's one bar hidden fairly in the middle of the screen, which contains some PvP macros/trinkets.
Bartender 3 + CyCircled as Bar mod.
SimpleMiniMap
Changed the fonts in the game
Pitbull (switched from aguf after it kept crashing every time I entered a raid and like some of its features more than I do aguf.)
ShadowHUD
Omen
Decursive
CTMod - though not using it for a lot currently.
EnergyWatch, Outfitter, Chronometer, Deadly Boss Mods, Cooldown Timer, SCT, CleanChat
Think that should be the majority of the important ones anyway.