@kalos72 You've hit on something there I should've mentioned earlier, since I plan to be streaming/recording a lot in this expansion I've decided to go to 1080p and bury the needle on the quality settings. I still think 4k, even with lower quality settings looks better, but Twitch REALLY doesn't like streaming 4k. That and my connection just isn't good enough to stream at that quality. So far, this is a very compact UI in terms of memory usage. Though, I'm adding more today and with the computer upgrade I've got planned I'm even less concerned about the memory usage issue than I already was, but that's a topic for another time.

Current AddOns pictured:
Bartender4 - There is only 1 Bar visible, just split into 2 rows. There are an additional two bars, one in 3 rows of 4 beneath the visible one and another 1 row bar between that and the stat tracker to the right. I keep additional less used abilities like AOEs and taunt there, along with professions. The long bar holds all of my travel stuff like mounts and hearthstone(s).
Chinchilla Minimap - This one's a new one for me, but I think it's got me. I really like having the Location displayed with the minimap, and the overall aesthetic.
Shadowed Unit Frames - This one's a little tricky, but I used the predecessor to this as far back as BC. The only real trouble I have with it is that you have to preposition frames entirely by x / y text location on the screen. That's not the most terrible thing in the world, and definitely what I prefer for fine tuning. But when I'm just getting set up, I really just want to be able to unlock it and move it in the general area where I want it.
Skada - Damage, Threat, etc meters. Still have some customization to do there, but I really love this addon.
TipTac - Really simple Tooltip addon that lets you move and configure the appearance of tooltips. Otherwise tooltips would cover Skada.

@Wubsie This is something I think we can agree on Bellular Gaming did a great video recently about his new UI that I think sums it up best. I'm trying to do similarly, in that I want the UI to display the information I need/want rather than just ALL of the information. Additionally, I'm going with the philosophy of conditional UI elements. Such as the Part/Solo bars. That's the major thing I'm tackling today (along with Clique integration). In a group, the play bar will become part of the group window. That's the plan anyway. When I break out the raid however the player window will disappear completely in favor of a raid grid.

I used to use oRA long, LONG time ago. I might have to have a look at it again, probably that or WeakAuras. I may, in the end hide the last action bar when it's all done. But I'm not entirely sure yet. I've left the Extra Action Button untouched at this point, I'm not entirely sure what I'm going to do with it, I might move it to the top / center of the screen (just under where I put the Micro Menu Bar).

@ebony I think upgrading my monitor is what made me change my philosophy toward what's on the screen, when I realized how gorgeous the scenery really can look in the game I wanted to see more of it.

Some parting thoughts:
I've decided I'm definitely going to be adding a hidden Healing bar somewhere, I plan to upgrade my mouse in a bit. And the eventual goal is to move all healing to clique on the mouse itself with movement and attack rotations handled by the keyboard. So, expect more a bit later.