You're UI is way to overcrowded for my taste. I'll give it 5/10. I saw you were asking what addons he's using, you can check
this link for some nice addon compilations examples.
My UI
What I'm using:
Dominos => Bar Frame
Shadowed Unit Frames => Unit frames, doh.
pMinimap => Simpler minimap
Minimap Button Frame => it displays all buttons that usually are around the minimap in a frame.
Quartz => Casting bar
Satrina Buff Frames => Buff frames, this is an awesome addon, can do alot of stuff if you take the time to configure it.
ArkInventory => Inventory
Vuhdo => Raid Frames (in case anyone cares, Vuhdo has better cpu management then Grid and Healbot, and many more options)
Clique => hotkeys for skills
InspectEquip => an addon which shows where an item came from. If it came from a raid or if it was bought with emblems. It's pretty useful, for me atleast.
GearScore
ElitistGroup => Displays stats regarding gear (gems, enchants) and raiding experience.
DeadlyBossMod => Boss encounters
Ludwig => Item Database
Mapster => Map addon, makes it movable and resizable.
Button Facade (Caith skin) for button skins.
Doom Cooldown Pulse => An icon appears on your screen when an ability's cooldown is over.
