What's the oldest system you still use, and what keeps you coming back?

[Pajderman]

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.