Seventh seems to be the best on a market and audience perspective. There were about 500 million units sold between DS, PSP, 360, Wii, and PS3, The vast majority of my gaming from the seventh gen is the Wii and DS. I played some 360, a little PS3, and no PSP.
If I have to pick a favorite: Eighth Generation. If you count Switch in there, then that makes my case further (Breath of the Wild, Odyssey, SSB Ultimate, Three Houses). Even without the Switch you still have a variety of fantastic games on PS4, 3DS, and even some on Wii U. I didn't mention Xbox One because I don't have one and there are virtually no true exclusives.
Gen Eight Faves: Fire Emblem: Awakening, Animal Crossing: New Leaf, Super Smash Bros. for Wii U, Stardew Valley, Marvel's Spider-Man. And if you count Switch; The Legend of Zelda: Breath of the Wild, Super Mario Odyssey, Super Smash Bros. Ultimate, Fire Emblem: Three Houses
On this generation talk, I would label each generation as this...
1st: Dedicated Consoles
2nd: Cartridge Games
3rd: 8-bit Era
4th: 16-bit Era
5th: Early 3D Era
6th: 128-bit Era
7th: Largest Market Generation
8th: HD Generation
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima