NDS. What keeps me coming back are the DQ 4,5 and 6 games.

PS3 since my music and videos are stored on there. Back when you could still download you tube music videos without commercials. I also still use it as a blu-ray player as it's connected to my HDMI 1.4 amp directly and is the only capable device to deliver lossless 24bit 192khz 5.1 surround for Akira and a couple others.

Second generation I believe, they were out in the early 80s alongside the Atari 2600, Colecovision, Intellivision, et al.

That would be my eTim RGB Modded NES Toploader. I have a PCEngine and SMS as well, but the NES is the oldest system I have (if you ignore that the Toploader came out in the 90s). I just got a Commedore Vic system, but that's not as old as the Commedore 64.

As for why it keeps me coming back? It just has so many hidden gems that most gamers don't really know about. Mario, Castlevania, and Contra are just the tip of the iceberg. There's over 100 solid games for the system and the two button gameplay just works.

Recommended games for it are...

Adventure Island 3
Adventures of Lolo 1-3
Baseball Stars
Battletoads
Bionic Commando
Master Blaster
Bucky O'Hare
Burai Fighter
Castlevania 3
Clash at Demonhead
Conquest of the Crystal Palace
Contra & Super C
Crystalis
Darkwing Duck
Double Dragon II
Dragon Warrior 3 & 4
Gargoyle's Quest II
Guerilla War
Gun Nac
Isolated Warrior
Journey to Silius
Kabuki Quantum Fighter
Kirby's Adventure
Zelda
Long Ranger
Megaman 2
Metal Storm
Mike Tyson's Punch Out
Ninja Gaiden 1-2
River City Ransom
Shadow of the Ninja
Shatterhand
Star Tropics
Mario 3
Turtles III
Terra Cresta
The Guardian Legend
Tiny Toon Adventures
Ultima Quest of the Avatar
Vice Project Doom
Zen Intergalactic Ninja

^All of those games play just as well as any modern indie. I avoided the acquired taste games in my collection.

Steals for their own list of good NES games.

Offers some games from their own list of cool games not on Switch Online in exchange.

Adventure Island 2

Destiny of an Emperor

Faxanadu

Gun.Smoke

Jackal

Little Nemo: The Dream Master

Little Samson

Marble Madness

Panic Restaurant

Power Blade

Street Fighter 2010

Willow

This is equally as significant as the swapping of audio cassette tapes from the moon landing mission.

I play GameCube with family still. Mario Kart Double Dash and Donkey Konga, a couple of times a year.
I also have a modded GBA that I use on trips where I want to keep light packing. Play it at home from time to time when I need my GBA Fire Emblem fix.

I do play a lot of older games but on newer hardware. With GameCube games arriving on Nintendo Switch Online I might put my GameCube in the attic if/when I get a Switch 2 and Mario Kart DD get released for it.
The GBA, the first system I bought with my own money, I will keep forever.

My good old Xbox 360. I still use it only for games that are not backward compatible with Xbox Series X :)

I still play on ps4 mainly to play ps2/ps1 games.

I almost exclusively play on ps2(90%) and ps1 ,xbox etc.

The sheer amount of games i still want to play on that system is endless,and modern games just are not for me anymore.

Atm working on.
Star ocean till the end of time
Dynasty warriors 4
Crimson sea 2
Girl!! why do you have such big one's?(jp import)
Metal slug 3d

And the list of games i still need to start is in the hundreds

PS2 and Dreamcast.

Interesting distribution in the polls; big spikes for the 7th gen (makes sense as a lot of PS3/Wii/DS/PSP games aren't playable on modern consoles) and the 3rd. (Presumably cos a lot of folks entered gaming with the NES and still play on it)

My oldest is the SNES I got for Christmas 1994; it stills works fine and every now and then I feel like playing through Starfox or Donkey Kong Country again just to relive my childhood and the games that made me fall in love with Nintendo and gaming as a medium.