Thanks for the script. Found a slight problem though: with database names that have funky characters in them, especially a period, this will throw an error (as wakanni found). I placed brackets around the @vcDatabaseName in the EXEC statement:

EXEC ('

INSERT INTO ##tbl_DataSize

SELECT CAST((SUM(size)) as DECIMAL(20,3)) FROM ['+@vcDatabaseName+'].dbo.sysfiles'

)

No more errors for me.