[CentOS] Recommended Configuration Control Software?

We have several dozen production Linux servers and I would like to have better control over what files are changed, by whom, when they were changed, etc. Because these are all production servers that are in use 24x7, we do not have the luxury of simply doing a clean build, taking md5sums of each file, and then doing fresh installations. I need a system that can take in-place snapshots of each server's configuration files, store them in some kind of database or text file, and notify me whenever something changes.

I've used tripwire in the past - do you have any other recommendations for this type of project?