Atari 400 and 800 were released late 1979, 3 years before C64 and ZX Spectrum. Atari 800 sold quite well in America and became THE computer to own because of it's amazing graphic capabilities. Everything on Atari 800 was super smooth, from the scrolling to the colours.
There were lots of games and appz released for Atari's 8 bit computer back then.
Now to the funny part.
Both ST, ZX Spectrum and C64 sold more then Atari's 8bit computers. Yet Atari 800 seems to be more supported today 34 years after it's release then it ever was back then. New games, remakes, demos, appz and conversions is released all the time while emulation is improved. People even type in all the listenings from all the old computer magazines for anyone to download.
Atari 800 is much alive today too. I'm glad to see that as an old fan of Ataris amazing 8bit computer from 1979.
My first contact with Atari 800 was some screenshots on early games like Thorn Emi's Submarine Commander and Jumbo Jet flight simulator. I thought, wow, what a far out computer, unfortanly it's too expensive for me to buy and a year later i had a Commodore Vic-20 on my desk.
Well, Always check Atarimania, Fandal, Homesoft, Atari Online Polen etc for all the latests games, demos and appz.
Fandal
http://atari.fandal.cz/index.php
Homesoft
http://www.mushca.com/f/atari/
Atari Mania
http://www.atarimania.com
Atari Online Polen (use the sites translator for english)
http://atarionline.pl/v01/index.php?ct= ... 1374731402
Atari 800 Win
https://github.com/Jaskier/Atari800Win-PLus/downloads
Altirra
http://www.virtualdub.org/altirra.html
For a complete Tosec, check this link
http://archive.org/details/Atari_8_bit_TOSEC_2012_04_23
While you're here, download the Tosec for ST too
http://archive.org/details/Atari_ST_TOSEC_2012_04_23
(but beware, it's 13.9 Gb in size)
And...
Don't forget this excellent FTP

ftp://ftp.pigwa.net/stuff/collections/h ... olmes%201/