This has been done a great many times I know, but to be frank, I don't touch my UI very often unless one of my friends beats me with the verbal sticks and yells "BAD PEDRAN!"  (aka, not having PallyPower by accident one raid b/c kids turned it off)

So since I'm re-setting up and re-designing my UI next time I login, I figured I'd see what ya'll think I might be missing, or what you prefer instead of one that I have.

• BugGrabber - Not a UI thing, but there......
• DF Raid-Pack
• FuBar
  • I usually put Dominos, SmartRes, a UI-Restart Button, RatingBuster, Omen, and Grid in my FuBar
• LuckyCharms
• Outfitter - Never used it before, but with Dual-Spec.......
• Bartender4 / Dominos - Personally I can't tell much difference between the two though Bartender is a little more 'tech'.  I've always used Dominos, but I'll be getting Bartender4 b/c Dominos hasn't updated for 3.1 yet.
• QuestHelper- I'm a lazy SOB
• Talented - Ghli recently introduced me to this WONDERFUL addon for exporting wowhead talent-sets directly into wow.  No more screwups for me.
• Pitbull - Yes, yes, I know.  I hate myself too.

I'll also be using the following:

 /console SET mouseSpeed "xx" (I usually play around till I find a good number, but it's been almost two years... I believe the safe zone is either 0-10 or 0-50)  This is mouse-dependant since each mouse has it's own DPI.

 /console SET cameraDistanceSmoothSpeed "14"

 /console SET cameraDistanceMax "36"