Minecraft - Find a solid teamspeak community, get some modpacks and launchers and have a blast.
CS:GO - If you want to try comeptitive FPS
Civilization V
Kentucky Route Zero
Starcraft 2
Pillars of Eternity
Portal 1 and 2
Divinity: Original Sin
Dota 2 (takes a long time to get good but amazing)
League of Legends (if Dota2 is too hard and you have friends that play it)
Heroes of The Storm (If you just want to have fun in a MOBA)
Skyrim (Depending on the mods and PC specs, you could play a game that looks 50x better than any console game ever released)
Witcher is skippable, Witcher 2 is fun if you never played, but I prefer Witcher 3 and its great on PC
Just Cause is beautiful on PC
Torchlight 2 is also cool.
Cities: Skyline is also a really cool game.
A teamspeak community is essential if you want people to play new games with. Or Steam friends.
If you want the TS I use, they play all kinds of different games, PM and I will give you the server info.
Right now they are hooked on Trove and have been playing WoW a tad.
Here is a GIANT list of PC exclusives releasing in 2015, 2016, and 2017.
http://www.gamespot.com/forums/pc-mac-linux-society-1000004/big-pc-exclusives-of-2015-2016-2017-new-31154099/
Makes consoles look incompetent.
This also may be useful for ya. http://www.pcgamer.com/best-pc-games-2015/
