I still use Wordstar 4, c. 1987. For a quick letter, it does all I need and generates text files which can be string-searched easily.
Old software is great value. Photoshop 7, Corel Draw 11. It is usually less buggy than new stuff because by the time you buy it they have fixed all they were going to fix.
The only drawback is that if you upgrade the O/S, say to Vista, a lot of stuff stops working. But then why upgrade the O/S? It's only a piece of software under which one runs applications!
That oldversion.com site is curious - one can download e.g. Cool Edit Pro 2.0 which is relatively recent. How do they work this??