Cool! Thanks everyone for the help. While it turns out that I didn't need
to reinstall, I really wanted to put Slackware on this system (since it's my "server" and all). So, I repartitioned hda (and left /home on hdb) and put Slack 9.1 on the box, using the entirety of the 10GB drive for /, /boot, /swap, /usr, and /var. / and /usr got a lot bigger.
As it turns out, it only took me about three hours (this time did include cuddle-time with the kids, dinner, "The Cat in the Hat", and about an hour's worth of network TV) so you can see it was not a huge investment. I'm informed that it will have great returns. Reports on that later.