TunhUI

It's back! And it's modular! (well, kinda...)
Like the addon, but prefer a smaller castbar? Hate the addon, but like the unit frames? No problem, just choose which modules you want to use.
Among the other additions are a reworked right panel + map, movable frames (cast bars, etc.), a shiny new XP-to-level-up count-down display, and an overhauled display for runes, holy power, soul shards, and combo points.

Tunhguod UI is a UI overhaul designed to consolidate combat-relevant information for better visibility, and look pretty slick at the same time. This is effectively a mashup of every feature I think a good UI should have including an action button panel which mimmicks your physical keyboard layout, good buff/debuff/cooldown bars (logarithmic, of course!), unit-frame click-casting (requires a mouse with more than three buttons), and more.

The action button panel supports user-defined "states" triggered by different combinations of macro-like events (modifier keys, character stances, friendly/enemy target, etc.). Unit frame click-casting allows spells to be cast on party members without ever changing targets. 'Idiot lights', or configurable aura/item/spell indicators, allow to you to spend less time watching for buffs and procs and more time on fight mechanics.

This addon does enforce a very strict keyboard layout. Every keybind from 5/T/G/B left is overridden while the addon is in use. I know that, by default, a number of shortcuts are bound to these keys (such as "B" to open bags"). The goal is to make the most of your most valuable keys, those close to WASD (or ESDF) - however this layout might not be to everyone's preference.

This addon is still in very early beta

Do not install this addon unless you're comfortable working with something that isn't quite complete yet and is likely to change a great deal in the future. I highly suggest testing this out on an alt before you reconfigure everything for your main.

Class support:

• Mage: Complete
• Priest: Complete
• Death Knight: Complete
• Druid: Needs balance bar
• Rogue: Complete?
• Warrior: Complete?
• Warlock: Complete
• Hunter: Needs pet bar
• Shaman: Complete?
• Paladin: Complete

Untested:

• Arenas

Bug reports should be filed here. Suggestions are always appreciated.