We didn't have the 2600, but we did have the 5200, and the 7200. The 5200 only had a couple limited games, played River Raid, and a baseball game the most.
On the 7200, which played all of the original 2600 games, Adveture, Dig Dug, a pinball and football game, were the ones we played.
However, IMO my absolute favorite without a doubt, was Pole Position. The OG of driving games. I played for hours and hours.
Classic 80's commerical
http://www.youtube.com/watch?v=Om84Zc4-KcQ