My UI doesn't really change when I go hunter to rogue, I really just gain a pet bar.
Here's a few screenshots so you can get an idea what I'm using.
#1,
#2,
#3,
#4,
#5 #1 is a shot from me in (practice) arena a little while ago. #2 is a configuration shot, though I've changed a bit since then; the target buffs/debuffs are still the same, though. #3 is a typical combat shot, with the Intimidation debuff up on the target, shown both in the debuffs and by NECB. #4 is a combat cast bar shot, showing my shot timer as well as a cast bar going over the mana bar of my target. #5 is a simple cast bar shot, both of mine and my targets.
The unit frame addon is one not a lot of people use, because it's a little obscure. UnderHood is the name of it, and it starts as pretty much a HUD. It's really nice, though, as the frames and buffs allow me to click through them, so really the only thing that I can click of them is the name of my target. I can move pretty much everything independently of eachother, which makes it really nice for custom setup. As you can see, I've set it up so pretty much everything is in one place in the middle of my screen.