Actually, Deluge seems to re-break itself pretty quickly again after removing those files. I tried a few other things to try to fix it but so far am not finding anything that works. I think I will be switching to another torrent client in the future, which is sad because I really liked Deluge, but t...

I have the same problem and I registered on this forum to suggest deleting or moving the ~/.config/deluge/state/torrents.fastresume and ~/.config/deluge/state/torrents.fastresume.bak files. After you do that, then try launching Deluge again. Worked for me.