What software do you use to audit your machines?

Hello:

I just wondering what software everyone uses to audit their
machines... to keep track of things like installed programs, versions,
configurations, etc.

I know Windows has the Add/Remove Programs contral panel app and some
things can be derived from scripting... but I'm looking for a total,
centrally administered solution -- looking for a program or a suite of
apps which takes the work out of CM -- NOT a disjointed solution of
running dozens of different scripts for example.

Also curious about if the application you use has an API and/or can
work with multiple operating systems. I've tried to google these last
two capabilities and haven't been able to find squat.

Suggestions are greatly appreciated.

Thanks!