Okay, I admit it, Blizzard's standard UI has, for the most part, been perfectly fine for me ever since I began playing the game back in December of 2006. Wow, has it been that long already? 12 ability hotkeys and the additional toolbars were all I seemed to need. Other add-ons like Questhelper, Recount and Omen really don't take away from the standard UI. For general play and basic PvP, there is little wrong with Blizzard's interface.
This brings me to arena, the subject I've been most focused on the past weeks. Since our 3v3 progress essentially reached a standstill, I stepped back and began to analyze what has been going wrong. First and foremost on my short list was my inability to easily trip all my abilities and spells when I most needed them. In a heated and generally very short arena match, looking away from your quarry to try to click on an ability on another part of the screen is doubly ineffective; it takes extra time to hit the button, AND you lose out on valuable moments when you could be striking, interrupting, or otherwise harassing your target. Thus, I reluctantly began to look for ways to improve my UI.
I say reluctant, because I'm generally not one who likes change, especially not after three straight years of being in a "comfort zone" with my controls. So, this has become more a forced effort than I was expecting. After a rather laborious research period, I found several key addons that I have implemented to try to improve my UI. They are, in no particular order:
1. Gladius - Arena addon that tells you the build of your opponents, sends messages to your team regarding critical events (like when the enemy uses a PvP trinket), and more.
2. Pitbull - This addon drastically changes the appearance of your UI - it basically does away with the standard target and party frames and re-introduces them in a completely customizable way.
3. Dominos - This is a unit fram editor that finishes the transformation that Pitbull starts, and lets you customize every other aspect of the UI - especially the action bars.
4. MSBT - This alters the default scrolling combat text and adds in more functionality.
5. Cooldown Watch - Gives you small, customizable countdown bars that tell you when your cooldowns will be back up.
All of these are amazing addons, but they are not for the faint of heart. They all must be heavily customized to suit your needs, and often do not function at their best "straight out of the box." The biggest thing I've done with my UI so far is to put two large unit frames on either side of my toon on the lower middle part of the screen - one for my info, and the other for my target. There are many other mods I have done as well to the UI.
It is clear that the UI I've made is becoming purpose built - it is not the best suited for standard PvE any longer because of the information it shows, but so far, it seems to be doing what I'd hoped - providing me with quick information at a glance.
Add in the fact that I've finally broken down and begun to map my spells properly to hotkeys surrounding WASD, and I think I have come a long way. Early testing in BGs and Arena seems promising.
So, if you are serious about PvP and are not afraid to roll up your sleeves and mess around with some highly useful addons, I highly recommend doing so. At the very least, I am now able to use all my abilities without looking at the screen. Learning which ones are which (by feel) is another story! But, I'll get there.