Total Annihilation + expansions released on GOG

[Indy500]

http://www.gog.com/en/gamecard/total_anihilation_commander_pack

For $5.99 and with 64-bit OS support I don't think you can go wrong

Of course, you get the manual in PDF, soundtrack and the map\mission editor as post-purchase downloads as well.

For third party content, this is the place: http://tauniverse.com/

 

[Indy500]

wow the graphics have aged badly

i know, i know it has amazing gameplay and i had the privilege of playing it on LAN with friends from school when younger but not sure id want to play again after looking at the screenshots

I think the polygons look better than the sprites of RA\C&C and Starcraft, but each to their own.

Edit: Supcom's interface has spoiled me, I keep trying to do stuff that the TA interface won't allow, like dragging waypoints\construction orders around after placement