It's always been Meta in the config file, apparently either your keyboard used
to bind Meta to Alt, or Sawfish used to pretend Alt was Meta. How is your
keyboard set up?

It's a Happy Hacking keyboard, with DIP switches 1 and 2 on and the others off,
which apparently makes my '<>' key behave like a Windows key.

Perhaps I'm mistaken.  I've just noticed that my 'Alt' and '<>' keys are in a
different order to my Windows key and Alt key on all the other keyboards I've
used..

It's certainly true though that on the HHK 'Alt+Tab' does NOT cycle through
windows where '<>+Tab' DOES, and the configuration is 'M-TAB' for cycle and
'meta' for modifier key, but on another 7.1-beta1 machine 'Alt+Tab' DOES cycle
and 'W+Tab' does NOT, with the same configuration.

I guess it's just a weird HHK thing.  NOTABUG I guess.

If you want to know what keysyms your keys are actually sending, you can use
"xev" to look at key events

On the HHK, Alt produces Alt_L and <> produces Meta_L.

This bug was caused by a change in keyboard mappings in XFree86 a while
back which bound Meta to the Win keys.  I have changed it back to ALT
for the 105 keyboards.  XFree86 4.0.3 from seawolf should do the job.