Taking a concept to its logical end

The majority of my UI elements are hidden while I'm not in combat and/or don't have a target selected.This keeps down the clutter and lets me appreciate the game world a bit better.

Aside from the giant green minimap, the first thing you'll probably notice is that everything is clustered in the middle/bottom half of the screen. This is a deliberate design decision based on what I've observed about my own in/ability to readily see things located at various parts of the screen.The third image is an approximation of my screen viewing ability, with green being the most accessible and black/orange being completely inaccessible.

Eye dominance is the major factor here. I am left eye dominant. Centering on the middle of the screen effectively blacks out the far left side because I have only poor peripheral vision from my left eye, whereas my right eye contributes to a greater deal of awareness to the right half of the screen. The height/distance and overall positioning of my screen relative to my eyes also play a role in this.

UI Element Breakdown

Player/pet frames - I usually see the mana/power bar located directly underneath the player health bar on most UIs. I have instead replaced it with my pet's health bar, because I use a separate focus bar. This was done by adjusting anchor offsets on Shadowed unitFrames.

Target frames

Focus bar - Quite possibly the most important part of my UI. This bar is from IceHUD, There's a matching Alt.Power bar on the left side that shows up for things like Flamethrower heat...

Trap CDs - these are two small Power Auras that show up as stars when the trap is available, or displays the remaining cooldown (in seconds) when unavailable. Obviously, the blue star is for frost traps, and the orange star is for explosive trap.

Stunbreak CDs - Master's Call and Every Man for Himself (the human racial skill).

The wings are static artwork, though I also use them as the basis for certain triggers, such as the smaller set of wings in the combat screenshot (the small wings indicate that my Steady Focus buff is active, and will flash when about to expire.) The golden orb in the center was inspired by the Guild Wars 2 endurance bar. It empties when I use Disengage and fills back up while the skill is on cooldown. It also doubles as a range indicator (the text in the center of the orb).

Gnosis is as much cast bars as it is timer bars. It very effectively surpasses other cast bar addons like Quartz, and I would recommend it as a cast bar in its own right! Where it really shines, though, is its extremely customizable timer bars. The syntax takes some time to learn and I'm still far from proficient, but it has already proven invaluable for its ability to use npc id as a trigger/conditional. Also, you can even use Gnosis to play sound notifications.This essentially means Gnosis can be a 'DIY boss mod,' with notifications specific to individual boss mechanics. I currently have a large cast bar made with Gnosis that shows important, interruptible boss mechanics - but only when my interrupt is off cd, so it's not cluttering up my screen when I can't do anything about it anyways. You have incredible control over when, why and what displays on a Gnosis bar. It gets furry when you try to stack too many conditionals together but that issue can be bypassed by creating two mutually exclusive bars that take turns showing up.

Power Auras is the original addon that Weak Auras was created to expand upon. Its animation options are limited compared to WA (PA's only timer support is being able to display time/stack numbers, no growing bars here!) but support much of the same triggers in an interface that's easy to set up and doesn't require paging through multiple tabs. Unfortunately PA is somewhat behind the game updates and doesn't support talent choice detection.

Raven ... I'm honestly surprised how few people I've played with use or even know about this addon. Raven specializes in buff/debuff and cooldown bars. It effectively tracks multidots and its visual style fits well with my UI. Raven is somewhat lacking on the conditionals (it lets you choose from some presets such as primary/secondary spec, combat status, etc., but does not support further fine tuning. I would have liked to create a bar that only shows up when I have a particular talent learned, for example.) Gnosis picks up the slack in this area.

Aura Frames gets an honorary mention due to its excellent filters that can effectively turn its aura containers into small buff/debuff timers of their own. It also includes a strong sorting priority list.