I found ElvUI to be way too weird and didn't suit the game at all. Felt too sci-fi or whatever for my liking. I use the standard UI with a few tweaks:
http://i.imgur.com/n5JstXo.jpgI've used an addon called MoveAnything to well.. move stuff around! Such as the portraits, I moved them to each side of the cast bar, so I can keep an eye out for my own health and the target much more easily during battle. I also used the same addon to move the right-side action bar further down. Gryphons Remover, to remove the gryphons on each side of the action bars, because honestly I always found them to be a bit in the way.
The buttons you see next to the bags are my trinkets, using an addon called TrinketMenu that adds it's own UI frame for the trinkets that I can keybind. The one above is Gryphonheart items, which I'm sure everyone here knows of. xD
My damage meter is Skada, which I found to be quite a lot better (and less memory consuming) than Recount. Aside from these addons the only other things I use to change my UI visually is the fonts, which I believe are called Myriad Web. The fonts were part of a big UI addon pack I used in TBC, and I just kept the font since it's easier on the eyes than the standard WoW fonts imo (I tried going back to standard WoW fonts a few weeks ago, I only lasted 3 days before I changed back, it kept hurting my eyes).
And last but not least, my bag addon, Bagnon, which combines all the bags into one single inventory which in my opinion looks much better, and it also comes with a search function for your bags and bank, AND it lets you check out your alt's inventories/banks from any other character. Screenshot of Bags here:
http://i.imgur.com/tTy2hLj.jpgA little messy right now because my banks and void storage are full, and I have so many items I don't want to get rid of! (Gief Legion wardrobe soon pls).
I do use a few more addons but those are just stuff like DeadlyBossMods, Mogit and Atlasloot.