This is a very useful SQL script to listing all of the tables in a SQL Server database with the row count and the amount of space being used by that table, handy for troubleshooting databases that are using more space that expected.

CREATE TABLE #RowCountsAndSizes (TableName NVARCHAR(128),rows CHAR(11),      
       reserved VARCHAR(18),data VARCHAR(18),index_size VARCHAR(18), 
       unused VARCHAR(18))

EXEC       sp_MSForEachTable 'INSERT INTO #RowCountsAndSizes EXEC sp_spaceused ''?'' '

SELECT     TableName,CONVERT(bigint,rows) AS NumberOfRows,
           CONVERT(bigint,left(reserved,len(reserved)-3)) AS SizeinKB
FROM       #RowCountsAndSizes 
ORDER BY   NumberOfRows DESC,SizeinKB DESC,TableName

DROP TABLE #RowCountsAndSizes

The original details including some other useful scripts can be found using the following link:

 http://www.sqlmatters.com/Articles/Listing%20all%20tables%20in%20a%20database%20and%20their%20row%20counts%20and%20sizes.aspx