A checklist is a tool to assist the pilot to manage the aircraft safely.
As SSD states a well rounded pilot also has to be thinking about what he/she is doing.
The checklist is not there to tell you how to do it but is there to ask the pilot "Have you done this?".
Some commercially produced checklists are full of errors which contravene the POH.
Am not against sensible use of checklists but as an instructor there are times in a students training where I take the checklist away from them as all too often they are being used as a prop for incomplete knowledge as to how to operate the aircraft.
Any pilot worth his salt should be able to safely operate a simple aircraft without a checklist.