Oof, too many here too but again, interesting to see so many similar preferences. 
My current game time is mostly taken up by Path of Exile (if you like ARPGs, give this one a good try, it might be rough at the start but it's worth the time investment! I'm playing since closed beta, feel free to ask me anything, try @tk_Crassus ingame) and Darkest Dungeon, another Kickstarter that was money well spent.
Oldies that weren't just some fun on the side:
-Ascii roguelikes old and new
-Minecraft with the Millenaire mod (it seems pointless to me without as a singleplayer game) and the John Smith Texture Pack
-Metal Gear series
-Disgaea series + Final Fantasy Tactics + Tactics Ogre
-Final Fantasy VI to XIII, Suikoden 1
-Jagged Alliance 1 + 2, Fallout Tactics, X-Com/UFO + Xenonauts, Silent Storm + Silent Storm: Sentinels (they are awesome diamonds in the rough!)
-Elder Scrolls series, Baldurs Gate series, Ultima Underworld I, KotOR I
-the first two Katamari Damacy titles on PS2
-Shadow of the Colossus (the feels!)
-GTA series + Red Dead Redemption
-Tekken series, Rival Schools, Marvel vs Capcom series, Soul Calibur
-Doom I+II (11 year old me trying to explain to my mom why it's ok to use that chainsaw on pixelated humanoids)
-Diablo I+II, Titan Quest, Hellgate London + Mythos (I liked the map system better than what later became Torchlight)
-Civilization I, II, IV + Colonization, Transport Tycoon
-Horizons/Istaria, Dark and Light, World of Warcraft (from vanilla to about 4 years ago, don't like the modern overly streamlined version, loved the early RP-PVP days where you actually interacted with others)
-Demon Souls (still like the central hub a lot more than the Dark Souls style)
-Delta Force 2 and Joint Operations (liked it better than Battlefield 2)
-the old Call of Duty and Medal of Honor titles, Modern Warfare until Black Ops multiplayer, BF Bad Company 2 and BF 3 multiplayer (I'm way too slow for the every faster paintball style nowadays), Unreal Tournament series
-SSX 3, the older Tony Hawk titles
-Little Big Planet series and Borderlands with friends
-Monster Hunter series, preferably couch co-op or on PSP and 3DS while travelling
-Battle Isle II and History Line
-Gran Turismo series (bad games, great simulations) + Motorstorm series (when I just want to have mad fun), Midnight Club LA (pimp my ride), Burnout 1-3 (crash mode with lots of people
)
-Anstoss 1-3, Biing 1+2, Mad Tv (all great german managment games)