If you haven't already played them, I'd suggest getting Fallout 3 or Fallout New Vegas. They are both brilliant games, with long story lines. There are many different mods out for both games (literally, over 30,000 for both games I think?) so if you haven't already, check them out!

Ew those are the worst games that what that kid listed, try DayZ Standalone, Arma 3, League of Legends if you like strategy or Dota 2. Also you can get alot of cracked games out there for free but I don't recommend getting them I get them because there mostly all single player games like fallout & skyrim and assassins creed black flag for free,but anyways some other good games could also be Rust and Garry's Mod on steam also Arma 2 & Arma 2 DayZ Mod. Good free games that you can get on steam could be War thunder & Warframe and also Planet Side 2, Planet side 2 is awesome 2000 Player online servers is cool as hell also Team Fortress 2 is good also there's a lot more you just have to see for you self

Also it would of been nice if you can tell us your future PC Specs because I just listed a whole bunch a games I can run anyways good luck with your pc

TTKModz wrote Ew those are the worst games that what that kid listed, try DayZ Standalone, Arma 3, League of Legends if you like strategy or Dota 2. Also you can get alot of cracked games out there for free but I don't recommend getting them I get them because there mostly all single player games like fallout & skyrim and assassins creed black flag for free,but anyways some other good games could also be Rust and Garry's Mod on steam also Arma 2 & Arma 2 DayZ Mod. Good free games that you can get on steam could be War thunder & Warframe and also Planet Side 2, Planet side 2 is awesome 2000 Player online servers is cool as hell also Team Fortress 2 is good also there's a lot more you just have to see for you self

Also it would of been nice if you can tell us your future PC Specs because I just listed a whole bunch a games I can run anyways good luck with your pc

If you think Fallout 3 or NV are bad, you need to rethink your life. You can't drink from a woman's restroom toilet on TF2 now can you? (I'm kidding but seriously)
OP some I would highly recommend if you have never played them:
Dishonored
Mirrors Edge
Diablo III
Far Cry (any)
League of Legends
Minecraft is great when you have a lot of good mods
Tomb Raider
Any TES
Left 4 Dead 1 or 2 (2 preferably)
Portal 1 and 2. Get both if you can, but if not, get at least 1.
Borderlands
Civilization V
LIMBO
DMC Devil May Cry (look into it)
Castle Crashers or Battleblock Theater
Battlefield 3. Maybe 4.
Counter Strike: Global Offensive
Assassin's Creed IV
DayZ (when it is finally good to go)
BioShock series
Amnesia if you like horror games
Call of Duty 4
The Bridge
SteamWorld Dig
Garry's Mod
Dead Island
Dark Souls
The F.E.A.R series.

All those are great games, I recommend you get all of them at one point.