I use tellmewhen for many many things. It is a farily simple addon. It has 4 units of non clickable buttons that you can set number of rows/columns, and what buff/debuff/cooldown/etc is present on you, your focus, your target, etc. For example, I use expose armor often, but dont want to overwrite a sunder, so I have one icon that shows sunder, its stack count, and duration left. I use it to show unstable power, searing light, tought of light, touch of darkness, and just about every raid buff/debuff I need to monitor or die/kill someone else/wipe our raid.
Im using a version that hasnt been updated in a while, that I have made some custom edits to, but I still find myself reconfiguring it every fight. For example, I have 1 3 button segment that has icons roughly 20% the height of my screen devoted just to raid info. When we do twins I reconfigure it for touch of light and touch of darkness, then when we go to ulduar I change it to grav bomb and searing light. We hit freya and I change it to unstable energy, etc etc etc.
I have looked at, and in the past, used gridraidstatus, which adds center icon support for misc buffs/debuffs in raid encounters.
I am also using an addon called 'losecontrol' that puts an icon in the middle of my screen when I am cc'd with the duration shown via omnicc.
What I would like to see is all of this put in one mod. Id like too be able to create my normal tellmewhen icons, but Id also like to make a 2-3 button segment with 'raidstatusicons' which would populate based on the fight. Making the whole thing skinnable/buttoonfacadable, and having aceprofile support would be the icing on the cake.