Daytimer Organizer - my favorite PIM of all times. Never found a PIM so perfect ever again. It seems all PIMs become dumber and less customizable every year.
AMI Pro Word processor, the most easy to use word processor I ever worked with
Quattro Pro spreadsheet - the first spreadsheet that was actually fun to work with.
Synchronize It! and Compare It! - superb GUI design, I still use them to this day for small simple jobs - one can still buy them, they still work, but unfortunately not upgraded for many many years. Synchronize It! can even copy sparse files, which is extremely rare.