usability - The best practices for a rating bar/slider/buttons

I need to make a rating scale input device that satisfies the following requirements:

1) Each value must be associated with a number to the user.
2) It must be immediately clear that this thing measures a continuum.
3) It can't be pre-selected (making an actual slider all but impossible)
4) It must be adaptable to a number of different variables of differing levels of significance to the user.

I have attached my first attempt. It needs help.