My UI is probably very different from most people.
Firstly, it's not made to be pretty. It's made to allow me to see the information I need to in-combat at a glance. This is why I have a HUD, and why most of my candybars are in one spot. This is also why I play at full scale.
Secondly, it's made to keep all my information in one place, and only show it when I need it. The HUD/Cooldowns/Energy/Casts hide when they're full/complete. If I played a non-rogue, I'd probably set my actionbars to hide as well, but I need them out-of-combat (stealth). I have unitframes because sometimes I need to know more information than I usually do (All 40 buff/debuffs, actual HP, etc)