I would say the Xbox 360, tho I never really owned one. I feel it was maybe the most polished modern console, the most friendliest, worked offline (obviously), was easy to hack and MS didn’t really made a fuss about it. an x360 was accessible for everyone, even for the less fortunate peeps around here central-eastern and eastern europe. hacked or not, ms had a nice market here and the xbox brand was pretty stable.
The PS2, the og Xbox (though it really was a PC), the Game Cube, Wii, Wii U, and of course the 8 and 16 bit era consoles are also great candidates one by one.