The Rules For Community Champions
You should create distinctions you can give to people that have contributed a lot to the community. These must be difficult to achieve without being too difficult.
I suggest you spend a few hours setting a tier of distinctions. For example, the easiest distinction might be Community Veteran, then Community Champion and finally Community Protector (pick any names you like)
There are some rules about these distinctions.
First, don't give anyone a distinction in your community's first year – nor anyone that's been in your community for less than a year. The award has to have real meaning. Likewise, it should also be subjective, not based on any fixed points system. Reward the actions you want to see repeated, not the number of comments someone has contributed.
Second, the highest award should be temporary. A member should never have achieved everything he can get. Why not give the highest away to just one person for a limited amount of time, then decide who gets it next.
Finally, the distinctions must mean something. A community champion should have increased access to the site, receive free products/trials or, at minimum, have a better looking profile than anyone else.
Awarding titles is a difficult art. Give a title away too easily and it becomes meaningless (see honorary degrees). Set the bar too high and it becomes futile. What you need is a steady group of people willing to make a big difference to the community in return for recognition.