With my first post on these forums I'd like to thank you guys in this topic to inspire me to geek out for a night, and redo my interface.
Seeing all these screenshots here got me going on my own UI, but because I had a few raids upcoming I twiddled with an alt's UI to get the feel for it.
My main's UI is pretty top-heavy with Grid, my cooldowns and my target debuffs being in the upper corners, and so is my DK's (only lvl 80 alt). And it works, pretty much. I used to be a healer in the 40man instances, which cluttered up my screen so much I could hardly see. My current interface is a bit spread, but it keeps a much larger frame open for looking at what's happening.
My druid's UI in a raid

Grid shows running HoTs, my current target + last target debuffs are shown in dotimer under my current target, my cooldowns are at the right side (also dotimer)
And based on this same idea is my DK's ui.
Not the prettiest looking, perhaps. But it's worked for me so far.
Visible addons:
Bartender
AGUF + Grid / GridStatusHots / GridStatusLifebloom / GridIndicatorCornerText
ElkBuffBars
Prat + Minichat
Recount + Omen
DoTimer
Fubar: MiniClockFU / RecountFU / SimpleDurabilityFU / PerformanceFU / MCPfu
SimpleMinimap
ItemRack
This thread inspired me to try and make a cleaner, more bottom-heavy UI tho, so I got to work on my paladin, and my wee li'l lvl 11 priest. They're still WIP's, and I'll probably fiddle with it a lot before I actually change my druid's UI over. I want to get used to a new UI first, play some simple stuff on an alt, before I step into Ulduar and don't know where to find what.
So anyway, the results so far are these:

Paladin UI. As you can probably tell, I have a new found love for pixelfonts.
In idle, I only see my most important spells so I have something to look at. Minimap in right corner is a habit. My playerframe disappears when I am at full mana and HP, and out of combat, and have nothing selected. I don't need to see stuff like that when I'm idle.
In combat, 2 more bars appear with secondary spells like my Hands, Divine Shield, different seals, divine intervention etc. Focusframe appears on the left side, just above the chatwindows, I didn't get a screeny with a focusframe up (doh). I didn't get the chance to pop Grid up as my alt is horde, while my main is aliance.
Grid appears on the upper side of my playerframe, and grows horizontally for groups, then vertically for raids.
And my priest's UI, based on the same idea again, but with a little more familiarity towards the spell setup. This is probably the UI that will replace my druid's UI too, soon. (as there's less hassle tweaking and tuning it from priest to druid)
I'm still trying to figure out how I can get KGPanels to do what I want, so I can make some kick-ass borders to all those chatframes and actionbars...
Visible addons for these:
Bartender + Buttonfacade
Pitbull + Grid
SatrinaBuffFrame
DoTimer
SimpleMinimap
Prat + Minichat
Fubar: MiniClockFU / RecountFU / SimpleDurabilityFU / PerformanceFU / MCPfu
ItemRack
I'd appreciate feedback, this is my first grasp at an artsy UI

Any comments or tips or whines would be interesting to read.