OpenMW will keep Morrowind alive for a long time. The plan is to produce a game engine that can be used to make other games even, so we might see fan-made games completely different from Morrowind.
In general, I think TES will stick around for that long.
I wouldn't be surprised if ArenaNet last that long.
Some of the Dragon Age games would definitely be considered classic at that point, but we won't see them here unless EA goes bankrupt and Origins gets shut down.
Gede: Arx Fatalis. Still not on sale.
It's available right now -
http://www.gog.com/game/arx_fatalis