How many times has your database servers hard drives filled up and you want to find the culprit?  Probably not many but for me it happens all the time.  Here is a simple command to get a list of all sql server databases and their file size:

use master
go

exec sp_databases
go

Need to find out where the files are on disk?

SELECT [name] [Database], [filename] [File Path]
FROM master..sysdatabases