DatabaseSizesWithTotal.sql

SELECT      CASE WHEN sys.databases.name IS NULL THEN '--TOTAL--' ELSE sys.databases.name END AS DBName,  
            CAST(SUM(size)*8.0/1024.0 AS INT) AS SizeMB  
FROM        sys.databases JOIN sys.master_files ON sys.databases.database_id = sys.master_files.database_id 
GROUP BY    sys.databases.name  WITH ROLLUP
ORDER BY    SizeMB DESC