I went to the minecraft IRC channel. They were willing to help.
Apparently, typing "op username" in the TERMINAL (not the in-game "t" /prompt) makes that user admin. So I was typing "op spdorsey" into the in-game prompt and that was doing nothing.
I typed it into the TERMINAL (the system cmd line) while it was running the server and that worked.
One more thing. Creating op.txt or admins.txt and adding your own username to the list does nothing. The documents MUST be created by Minecraft automatically for them to work. Otherwise, Minecraft does not know to check them on launch.
After you use the CMD terminal to make an OP, it remembers after you quit the server.
Confusing. But now I know. I hope this post helps others.