Product design checklist

I always use a mental checklist that I run through on each design project, but since the car, I have decided to create and use a written one to go over during and just before the release of each project. This is my initial list, that I will refine as time goes on.  Every project can be developed a little further and it's not until I have released a project and been given feedback that I can come up with new ways to improve, but this list is to help get each project as far as I can first.  Hopefully it will help you too.

Beginning:
Have I come up with a brief or idea for a solution to a problem that doesn't exist? 
Have I done enough research?
Is this a concept for the sake of it?
Can the problem be solved another way?

Solutions:
Does the design idea address the need/problem sufficiently?
Has it been designed not just engineered?
Have I pushed the design far enough?
Am I churning out the same things as everyone else? Or is it being different for difference sake?
Is the detailing good or refined enough for each individual area on the concept?
Is there a balance between simple and complex areas?
Have the materials been properly considered?
Can it be engineered to be more environmentally friendly? (this will require a sub checklist) 
Have textures, colours and finishes been properly considered and pushed far enough?
Packaging where applicable?
Does the solution provide real benefit?
Is it too gimmicky - Does it have a very low gimmick rating?
Is it innovative in its size to complexity ratio.
Have I made everything thin enough, light enough, have I pushed the materials to their limits.

Publishing/presentation
Does it look cool in the images, is the quality as high as I can get it?
Does the presentation tell the story to someone not familiar with the project?