What rights should you grant or deny?
- Are you comfortable with anyone using your program?
- Are you comfortable with anyone modifying your program?
- Are you comfortable with anyone selling your program?
- Are you comfortable with anyone selling modifications of your program?
- Are you comfortable with somebody selling your program as closed source?
This are questions you need to answer on your own.
BTW, in my opinion GPL v2 or later is a safe default choice. It is used by those that answer 'yes' to all but the last of my sample questions.
