I’m usually not one for UI mods, but the GW2 UI Mod for WoW was good enough to convert me.
The GW2 WoW UI takes most of the Blizzard UI modules and makes them look like GW2’s interface. I’m particular to the center health globe with the split action bar as well as the simplicity of the target unit frame.
Depending on your class there are class-specific UI touches. The menu icons, minimap, and quest tracker are also nicely skinned.
All of the various modules can be turned on or off and moved. In terms of customization, it’s great.
If you’re like me and want a clean, minimalistic UI with all the functionality of the default WoW UI, then check out the GW2 UI Mod for WoW.