I like an UI (User Interface) with a clean look, with options that suit my playstyle. I move with my mouse, and use a Logitech G13 gamepad.
Sooo, my right hand is busy with the mouse, and left hand is on the gamepad.
Because of the mouse movement, I want the right side of the screen available for my mouse, without anything in the way. (That means the quest watcher had to go some where else.)
The addons with an asterix * I always have.
elvui. I have used tukui in the past, but tukui no longer supports lower resolutions. elvui is good! Most of the hardcore players use this UI.
*Chocolate Bar - ChocolateBar is a sweet display addon for broker plugins
iGuild, iFriends, BugSack, Broker Chat Alerts,
Bittens spell flash for rotations.
*GTFO - get out the fire!
*Pawn - upgrade info
Garrison Mission Manger
Broker - Garrison
I have a few more, but mostly just trying them out, or eye candy.
This is my banker/Auction House alt, so does not have much showing. The Quest Watch frame would be on the left.