Did you know you can use PowerShell to create an Excel list of all of the rules in your imported Management Packs? It's pretty easy -- just follow these steps:
sort-object -property MP | export-csv "c:\rules.csv"
Open the file C:\rules.csv in Excel and expand out the first column to get a view like this (click for larger picture):
The export-csv cmdlet that the output is piped into is a handy one to know about. You can use it to use to put information extracted with PowerShell into a comma separated format that can be read by Excel.
[Edit: Updated first line to clarify that this outputs rules for Management Packs that are already imported and to include link to larger picture.]
If you'd like to see outputs of a Management Pack's monitors and overrides (in addition to seeing a list