This list is pretty simple. I'm listing my favorite games that were not made by Bioware and involve no Pokemon. If I allowed those two, they would compose the entirety of the list. With that said, in no particular order, here they are!
Half-Life 2 and its episodes, Valve

A lot has been said about Half-Life 2, with good reason too. If you've played it, you know how it feels. Whether you're destroying Striders or running out of ammo in Ravenholm, the game, for the lack of a better term, succeeds. For those of you who have not played it, do yourself an immense favor and set aside some time to do so. I promise you, you will not regret it.
I am not a fan of FPSs, but while I play as Gordan Freeman, things are much different. The atmosphere is so Orwellian, so revolutionary that the story challenges that of story-driven RPGs. As you play, you'll journey through a variety of environments, utilize several vehicles, use dozens of weapons, and
probably definitely fall in love. Go play it now. Oh, by the way Valve, when the hell am I getting Episode 3?