Addon: Deadly Boss Mods

This addon is essentially required for any raiding and dungeon content. It can be active at all times and makes any player better. It will give warnings of boss abilities about to come off cooldown and even yell at you for standing in the fire! (yes, even the best of us stand in the fire for 50% of our health sometimes)

http://wow.curse.com/downloads/wow-addons/details/deadly-boss-mods.aspx