WoW UI Tutorial - pvptutorial.com

A good successor to the once-all-powerful NECB, Afflicted will allow you to monitor important enemy cooldowns and spells. For example, abilities such as Intercept and Blink can show cooldowns so you know when your enemy might suddenly teleport. Also, buffs such as Cloak of Shadows can be monitored with ease. New abilities can be added or existing ones can be removed.

You can find Afflicted3 at Wowinterface.com. Note that the video details Afflicted2, which may differ slightly in configuration from Afflicted3. The use and practicality of the addon is essentially the same.

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Another really good solution is Interrupt Bar. It's pretty basic, and you have to edit in spells you want, but it's pretty clean.

Here's a proof of concept of getting Two Interrupt Bars to stack on top of each other.