Directory and sub-directory usage utility

> WinXP Pro SP2
> Is there a utility that will show, graphically or textually, ALL WinXP PRo
> directories and subdirectories with the associated disk space used by EACH
> and EVERY directory or subdirectory?
> The Properties of each directory in WinXP Pro SP2 only shows the SINGLE
> directory and then calculates all subdirectories under it. I'd like to
> see
> what the usage is by directory and subdirectory in order to determine
> space
> usage on my laptop, which is getting pretty limited on the 80GB. 6GB
> left.
> Ideas and suggestions helpful.
> Yes you can email (!) money for a new laptop if you'd like!
> TIA!