Atari 2600
And the best game?
Zork I: The Great Underground Empire, originally released by Infocom in 1978, played on my oldest machine in 1983.
(http://www.infocom-if.org/games/zork1/zork1front_th.jpg)
Looks like this:
'West of House
You are standing in an open field west of a white house, with a boarded front door. There is a small mailbox here.
> ...'
It was endless. And had 126'426 bytes (huge!). Was ported from CPM to DOS, so playable today on XP. And it's free. Take a look at
http://www.infocom-if.org/downloads/downloads.html (http://www.infocom-if.org/downloads/downloads.html)
Far Cry is good, but I love Zork I.