This UI is my attempt at bringing everything together towards the lower center so everything you'll need is available at a glance. I ate up a bit of space with the experience bar and menu, but I thought it looked better down there, and as a former WoW player, I'm already used to looking down there for the menu.
The gap to the left is full of chat window, while the gap to the right has the tooltips.
Updated: 1.0; all is good. Finalized the Party placement (portraits were overlapping text before) and Party windows (uneven/large gaps between party member and target) and all is good. I'll update again if I feel like messing with Warzone and Operations Layouts, but for the main UI, I'm pretty much pleased. If you aren't running WUXGA (1920x1200) and would like me to create a version for your resolution, leave a comment, and when I get some free time, I'll give it a go.
Updated to 1.1 Okay, so I bet some people noticed that the target castbar and target of target castbar were swapped, compared to player castbar and focus castbar. Not anymore! Also fiddled with the achievement tracker and quest tracker, and tossed up the two new quickbars for subscribers. Been over a year since I last worked on this; hopefully if anything else pops up, I'll get on it faster.