Diablo and Diablo 2
Diablo 2 originally sold for $50 in 2000. As of January 2010 it still sells for $20 on Amazon and in most retail stores that carry games. The Battle Chest version still sells for $35 online and even $40 in stores. It also still shows up on top sales lists on Amazon and in the top 100 games on thepiratebay.org. Its obviously still a popular game to buy and download, let alone play. I think it is worth studying why this game has been so wildly successful and has stood the test of time, not only in terms of play, but sales.
The original Diablo apparently has been ported to the Commodore 64.  Of course the box for it only shows the IBM PC and Amiga screens. ;-)