The following will quickly list approximate rowcounts for all the tables in the database:

use DatabaseName

select TableName = o.name, Rows = max(i.rows)
from sysobjects o
join sysindexes i
on o.id = i.id
where xtype='u'
and OBJECTPROPERTY(o.id, N'IsUserTable') = 1
group by o.name
order by TableName