sudo: Ask for password for all commands except one

I'm trying to let my user run one special command using sudo without getting asked for the password. All other commands should prompt for password.

I've tried numerous entries in sudoers but none give me what I want.
user    ALL=(ALL) NOPASSWD: /bin/rpm

will let user run rpm with no password, however the user will no be allowed to run any other commands (using sudo)

I could do chown root /bin/rpm && chmod +s /bin/rpm but I would prefer a sudo solution.