Monitor database growth - a better way for sp_spaceused

This script is for anyone who has had issues in capturing the output from sp_spaceused, which returns two rows of different number of columns, therefore making it hard to capture into a table easily. I ran exec sp_helptext sp_spaceused and found the section where the two rows returned (I'm still confused why there are two select statements, one after the other, that don't have to be separated).

I did not keep the @updateusage portion of sp_spaceused and neither did I try to preserve the table check either via @objname (not needed for my purposes)

UPDATE: Oct 22, 2008 - Had a superflous variable here and there, so just cleaned up the code.