I'm using tellmewhen for a long time, and its simply amazing. You can keep track of any DOTs you have, buff, debuff(on you or target).
And the fact that's using the spell icon is perfect, since i'm a more visual person.
I keep track of Engulfing magic(valiona), lightning rod/waterlogged(council), and when i get those debuffs a big 2in by 2in icon pops right in my face hehe
Very usefull and friendly user.