If you want to watch the debuffs that are on you, you should be reading the debuff icons that are displayed in the HUD. The debuffs on you are on the left side of the HUD directly below your name in Player/Target and Health/Power and just to the left of the health race bar in the simple HUD.
There is a *very* detailed post on this topic here:
http://www.wowinterface.com/forums/s...28&postcount=2