Doug, you proved my point precisely, in that I can't imagine that people who need more than what typical web mail offers would be very impressed by GMail. Most people as you've said would be happy with any decently functioning web mail client and there's plenty of evidence around since Yahoo and other still have relatively high usage numbers. Then there are those people that use Facebook exclusively.

I don't even keep a very significant number of rules in my local client, but many of the ones I do have are outside of the scope of gmail. I remember being extremely frustrated a few months ago when setting some rules for my parents' account, but I can't recall exactly what I was trying to do at the time. I did like the fact that I was able to set those rules up for them so they operated at google's servers before they would ever see the mail at their clients - I have set them up to fetch mail with the default Apple Mail app from gmail with IMAP, so they never use the web interface.