First off, let me say that if you have a good cable connection, I'd do a netinstall using one of the new Sarge installers (download one from
http://www.au.debian.org/devel/debian-installer), as it will be more up-to-date - Woody is stable, but (IMHO) usually best for servers rather than home use.
As for partitioning... well this can be a bit of a contentious issue, but for home use I'd use something along of the lines of:
/home 20 Gb
/ 20 Gb
/swap approx. 2 x RAM
Seriously though, you're pretty unlikely to need all that space unless you do some video editing or all night number crunching. Most of what you'll use for a home workstation will probably be on the first cd. Have a read of the Debian installation docs at
www.debian.org/doc, and also
http://d-i.alioth.debian.org/manual/en.i386/apb.html
Good luck - Debian is a great distro (may take some getting used to, but it's well worth it !).
Cheers,
mj