I'd say the 7th gen because of easy it was to play games and be social plus its the longest

4th gen I would say

4th-5th gen for me

3rd to 5th generation with peak in 4th.

This is pretty easy, 4th to 5th gen. At least to me. I actually think that video game golden ages depend on what point you are in your life. It was easier for me to get excited about games and love every minute of them when I was younger in middle/high school. Now... I enjoy games, but I generally have more on plate to worry about these days... I don't feel the excitement like I used to...

6th gen. Granted it was my first gen, but that's the gen we got Melee and Halo 2.

I would definitely say 7th gen. The biggest install base of all time and literally everyone was playing some game due to the Wii and mobile gaming. Trust me people we are not gonna see another 300m install base for a very long time, and we will look back at this last generation as the one that brought us a lot of "Firsts."

6th gen.

Most people with knowledge of the industry agree, its the early eighties. 

http://en.wikipedia.org/wiki/Golden_age_of_arcade_video_games

1991-2005

Those 15 years encompass the creative, technical, and artistic peak of video game design, in my opinion, with 1998 being the epicenter.