Let's say the PC doesn't count and you aren't taking into account backwards compatibility, emulation, online play, homebrew games, and the cost/availability of games.
I feel like I'd want to choose the PS3. Like the Xbox 360 it had a decent lifespan and a lot of games were produced for it. A lot of which are already some of my favorites.
The only things that would make hesitant are I feel like a lot of modern games are larger and have open worlds which I feel like that could be nice in the long run and many of my favorite games for the PS3 have been re-released.
Fair enough. I'd probably just go for the Xbox One in that case and deal with a few games still being moddable and supporting the keyboard and mouse as peripherals rather than give up on gaming