SET NOCOUNT ON 

DBCC UPDATEUSAGE(0) 

-- DB size.
EXEC sp_spaceused

-- Table row counts and sizes.
CREATE TABLE #t
(
    [name] NVARCHAR(128),
    [rows] CHAR(11),
    reserved VARCHAR(18),
    data VARCHAR(18),
    index_size VARCHAR(18),
    unused VARCHAR(18)
) 

INSERT #t EXEC sp_msForEachTable 'EXEC sp_spaceused ''?''' 

SELECT *
FROM   #t

-- # of rows.
SELECT SUM(CAST([rows] AS int)) AS [rows]
FROM   #t

DROP TABLE #t 

[Source: http://therightstuff.de/CommentView,guid,df930155-f60f-4f56-ab33-f1352ff091a1.aspx]