Latest Versions
If you've heard me preach about client health scripts for GPOs and client installs before, I thought I'd point you to what I think is currently the best version of that script out there today. It was written by my fellow MVP, Jason Sandys: http://blogs.catapultsystems.com/jsandys/archive/2010/10/19/configmgr-client-startup-script.aspx
If you've heard Sherry Kissinger preach about inventory, her friend and fellow MVP Mark Cohrane has a nice tool to help you add the mof edits to get that data back: RegKeytoMof.
Finally, Richard Zander's Client Center is another tool you might have seen at our meetings. This tool is great for troubleshooting one client at a time - when you're verifying patch status or figuring out why something didn't install.