My previous despair faded and I'm giving Gutsy another try. Configuring my disks so that I have two partitions available for OS installs made it easy to try things as I got the chance.
I finally found a combination of settings that appear to make my displays work and don't kill gnome-terminal. I'll attach my xorg.conf here in case I forget what it took.
Sound volume is markedly lower than under Feisty. But I simply turned up the volume on my speakers.
I went back through my old Ubuntu posts and redid the things that seemed applicable. Hopefully my update won't be too much trouble for Murray.