Heres a few more suggestions for the Direct Downloads. One game which I am surprised got little discussed in this thread was Karateka. It was created by Jordan Mechner of Prince of Persia fame and is like a cinematic International Karate. Check this game out if you get the chance. Heres a few pics of it:
The next one is a text adventure game based on the Hobbit. It was quite advanced for its time with its attention to details and also played out in real time. The other is Raid Over Bungeline Bay, the first game created by Sim Citys Will Wright.

-Think Way of the Exploding Fist with Prince of Persias cinematic presentation
-What a coincidence! It was done by Jordan Mechner!
-Mechners first hit game
-Has sound cues which were later used in Prince of Persia
-More information and strategy guide
HERE

-A text adventure game based on the furry footed, weed smoking hippie
-Had a pretty advance parser for its time. Capable of understanding Inglish.
-Its also a real time text game. Events continue on even when you leave the keyboard.
-There's an older version of the game which you can get
HERE
-More information
HERE

-The first videogame made by Will Wright!
-Realistic hellcraft controls!!
-360° scrolling screen!!!
-5 increasing levels of challenge!!!!!