I believe in the technical moral stand point it is fine to download games once the profit margins are no longer increasing for the games creator. I have noticed that many game companies tend to lower the anti-hacking technologies of games via a patch when the next edition of the game come around. One example is the game Sacred. Which the latest patch removes the need to have the disc in the drive for example. This patch came out around the time they released news about Sacred 2.
Needless to say that old school Nintendo games would still be ok in this moral light, except for the fact that Nintendo has done the devilish thing of renewing copyrights and re-releasing these old games on new platforms. (Repeating trend in entertainment. Look at all the cover songs top 100 bands perform.)
Primarily I am assuming you are downloading a game for 'free' and I hope this is what Tuck was going for on this discussion.