"Ok, that makes sense, but what do I use as the mount point? That was really what my original question was."
You can use any empty directory as a mountpoint. So assuming that your second drive is hdb and that you format the new partition as ext3 you can mount the new partition this way:
mount -t ext3 /dev/hdb2 /closet
or you can put an entry for /closet in /etc/fstab
Be prepared. Create a LifeBoat CD.