Recommendation for task management, something unobtrusive

[jankyhanky#WP]

I would like a task killer that just says how much memory an app is using, and an option to kill it. I would open the task manager only when I need it.
I don't want something that runs in the background. If the app closes itself, that'd be great.

Does anyone have a recommendation?

 

[ali.fazal]

Advanced Task Killer Free works great for me.

Although, some people say that Task Killers in general are bad for the phone's memory management, although nobody has ever successfully explained why.