After reading for months this topic, here is my own interface [\o/].
GOAL
The improvement of my UI was driven by the objective to perform in PvP as an Enhancement Shaman. I had to have at the same time a very clear UI and all the most important information.
INSPIRATION
Definitely
RothUI, my UI is just a tweaking of his great job.
ADDONS
What you see
→ Aloft : Nameplates (pTags wasn't filling my needs)
→ AzCastBar
→ Bongos3
→ cyCircled
→ EavesDrop
→ Fane
→ pChat
→ LynStats
→ MikScrollingBattleText
→ rBuffs
→ rUnits
→ StatBlocks
→ Cooling2
What you don't see
→ ArenaHistory
→ Proximo
→ Grid
→ Baggins
→ DRTracker
→ Afflicted
→ oTweaks
→ SpellAlerter