Half-Life, Halo: REACH, Team Fortress 2, Fallout: New Vegas. All of these games are gold but came from a time where you could still distinguish what reality was and wasn't.
and keep in mind that that's just the tip of the iceberg, all the mainstream stuff
there's a lot more games with great gameplay but with graphics that are dated today but adequate or even outstanding for their time (*ahem* my beloved Einhänder + many more)
