For those seeking ROMs, check out AtariAge.com ... from this page you can download pretty much every Atari 2600 known to man.
http://www.atariage.com/system_items.html?...&ItemTypeID=ROM (Don't worry ... "every Atari 2600 game known to man" comes out to be around three meg.)
As far as good games ... boy, I think a lot about the Atari 2600 is "you had to be there." I mean, anyone who has played Donkey Kong on MAME is NOT going to prefer the 2600 version (flaming barrels with only 2 different sprites, and only two levels).
Off the top of my head ... Asteroids, Slot Racers, Superman, Video Pinball, The Empire Strikes Back, River Raid, Pitfall, Freeway, Frogger, Missile Command, Keystone Kapers, Laser Blast, Stampede, Tennis, Demon Attack, Moon Patrol, and the classic Yars Revenge were some of my favorites.
You are right about one thing, as the market exploded the games went to hell. Try playing Kool-Aid Man and your head will explode in minutes.
Flack