The Hit List
Used by 4 peoplekarelia.com ↗

“I'm also trying to get accustomed to using The Hit List for my Getting Things Done lists.”
Daniel Sinker Interview, Director, Knight-Mozilla OpenNews · via Uses This 
“What ultimately won my heart was the Potion Factory's The Hit List, especially with the release of the iPhone app.”
Mike Krieger Interview, Co-founder of Instagram · via Uses This 