Yeah this.

6th.

The gamecube got soooooooooo much play time and awesomeness.

I would've said this one if you asked me before new year's, but a friend convinced me to play some GC with him, and the biggest wave of nostalgia hit me. 

Not so much a generation, but my favourite time period was the later 4th generation and the first two thirds or so of the fifth gen. Essentially the era when Rareware and Squaresoft were the two big companies. I like this generation and the NES generation as well. The 1st and 2nd generations didn't really matter to me, and the sixth generation felt like a weaker 5th generation with GTA to me.

The 4th, I loved the platformers on Gameboy and played Mortal Kombat, Street Fighter, Turtles Tournament Fighters and Killer Instint for endless hours.  When ever a new fighting game came out, I rented it and actually enjoyed it.  Plus that's the generation when I most enjoyed RPGs.

I did love the NES days though and now is pretty good too.

I have to say the seventh because i barely played last gen. I put so much hours in this generation, over 50 games beat.

I think it'll always be whichever generation I'm in.

5TH!!!!!!!

NINTENDO SIXTY FOOOOOOOOOOOOOOOOOOOOOOOOOOOUUUUUUUUUUR!!!!!!!!!!!

5th, followed by 6th, then 4th, 3th and 7th. 

4th gen by miles. Most of the best RPGs made to date were in this gen. And the platformers were top-notch, strategy and puzzle games were fun and addictive... I can go on.

Oh, though a small nitpick: Atari 2600 is only the second gen, not the first. First gen goes to the dedicated gaming systems like Pong and various 6-in-1 gaming consoles. Interchangable games was the big innovation of gen 2.

5th. The awesome N64 was my first console :)

Besides, very few games can beat the epicness of local multiplayer of Super Smash Bros., Goldeneye, Mario Kart64, and the Co-op of Perfect Dark. Yup Yup Yup.