Since patch 4.0 broke my old UI I ended up doing a new one. I’m still sticking to my favourite style of having everything at the bottom except for buffs. I just like having everything in one place. I realise this is probably not the same for everyone, and I admittedly move my Grid to a move central position on the screen when I’m playing my alt healer.
Shadowed Unit Frames
Classtimers (okay, you don’t actually see it on this shot, but I use it for tracking DoTs)
Satrina Buff Frames
Mik’s Scrolling Battle Text
In addition to those that are for the UI itself I of course use “the usual stuff” like Recount, Deadly Boss Mods and Omen Threatmeter.
One little neat addon I’d like to recomment though is Obituary. It’s something I find highly useful in raids. What it does is print out the killing blow of people in your party/raid in your chatlog so that you can see it without having to go into Recount/Skada to find it. You may still need to do that sometimes when investigating further, but I find it’s really helpful to get an initial idea, and you can immediately tell if someone stood (and died) in fire.