Finding table size in a database

I found this bit of code on http://www.databasejournal.com/img/BigTables.sql for finding the size a tables in a database on MS SQL Server. Really handy for finding out which tables are using up all the disk space!

/*****************************************************
*  BigTables.sql
*  Bill Graziano (SQLTeam.com)
*  graz@sqlteam.com
*  v1.1
*
*****************************************************/

declare @id    int
declare @type    character(2)
declare    @pages    int
declare @dbname sysname
declare @dbsize dec(15,0)
declare @bytesperpage    dec(15,0)
declare @pagesperMB        dec(15,0)

create table #spt_space
(
    objid        int null,
    rows        int null,
    reserved    dec(15) null,
    data        dec(15) null,
    indexp        dec(15) null,
    unused        dec(15) null
)

set nocount on

-- Create a cursor to loop through the user tables
declare c_tables cursor for
select    id
from    sysobjects
where    xtype = 'U'

open c_tables

fetch next from c_tables
into @id

while @@fetch_status = 0
begin

    /* Code from sp_spaceused */
    insert into #spt_space (objid, reserved)
        select objid = @id, sum(reserved)
            from sysindexes
                where indid in (0, 1, 255)
                    and id = @id

    select @pages = sum(dpages)
            from sysindexes
                where indid < 2
                    and id = @id
    select @pages = @pages + isnull(sum(used), 0)
        from sysindexes
            where indid = 255
                and id = @id
    update #spt_space
        set data = @pages
    where objid = @id

    /* index: sum(used) where indid in (0, 1, 255) - data */
    update #spt_space
        set indexp = (select sum(used)
                from sysindexes
                where indid in (0, 1, 255)
                and id = @id)
                - data
        where objid = @id

    /* unused: sum(reserved) - sum(used) where indid in (0, 1, 255) */
    update #spt_space
        set unused = reserved
                - (select sum(used)
                    from sysindexes
                        where indid in (0, 1, 255)
                        and id = @id)
        where objid = @id

    update #spt_space
        set rows = i.rows
            from sysindexes i
                where i.indid < 2
                and i.id = @id
                and objid = @id

    fetch next from c_tables
    into @id
end

select top 25
    Table_Name = (select left(name,25) from sysobjects where id = objid),
    rows = convert(char(11), rows),
    reserved_KB = ltrim(str(reserved * d.low / 1024.,15,0) + ' ' + 'KB'),
    data_KB = ltrim(str(data * d.low / 1024.,15,0) + ' ' + 'KB'),
    index_size_KB = ltrim(str(indexp * d.low / 1024.,15,0) + ' ' + 'KB'),
    unused_KB = ltrim(str(unused * d.low / 1024.,15,0) + ' ' + 'KB')

from     #spt_space, master.dbo.spt_values d
where     d.number = 1
and     d.type = 'E'
order by reserved desc

drop table #spt_space
close c_tables
deallocate c_tables