George,
I also use Notes. We are on v4.x but I've downloaded the R5 client at office and home. Notes has a lot to offer the Hall Of Shame, as you mentioned.
My mapisp32.exe shows version 5.5.1960.0 . The URL for the R5 client is
http://www.lotus.com/home.nsf/welcome/lotusnotes and you need to click on the "Build a Corporate Portal" symbol to download.
I was also able to access Notes mail through Outlook, and I don't need to enter my password. Setting it up was pretty straightforward. The only real problem with using Outlook is that the calendaring functions down't work.
All in all, I use Notes client at both desks for my business mail and Outlook Express for my ProFox list and personal mail.