In another salvo in the endless vi v. Emacs war, the ViM folks released ViM 7.0.
The announcement is about a month old. Why the delay for me mentioning it? Cygwin just updated their 6.4 to 7.0 over the weekend. Too bad the update removed vi from /usr/bin. Oops.
UPDATE: I found one source of my Cygwin trouble. For whatever reason, the ViM 7.0 installation put vim.exe and friends into C:\cygwin\usr\bin instead of /usr/bin. As my default Cygwin installation mounts C:\cygwin\bin as /usr/bin, that means the mount hides the files in the underlying Windows directory:
C:\cygwin\bin -> /usr/bin C:\cygwin\usr\bin -> hidden underneath
A quick unmount, switch to CMD.EXE, files moved to the right Windows directory, and remount: I can now run vim.
One remaining problem: whither the vi command?
UPDATE: Run the Cygwin installer/updater one more time. There is a patch up for the new ViM 7 package which fixes the missing /usr/bin/vi problem and the overall install issues.