So fellow /games/, I'm buying a high end computer next year (already got X360) and I'm doing a list of god-tier games to play.

Here's what I got thus far
Important:
Baldur's Gate: The Original Saga, Baldur's Gate 2 Complete, Dungeons & Dragons: Dragonshard, Icewind Dale Complete, Icewind Dale 2, Neverwinter Nights: Diamond Edition, Neverwinter Nights 2: Complete, Planescape: Torment, Divine Divinity - Almost done, Beyond Divinity, The Elder Scrolls III: Morrowind (+mods), The Elder Scrolls IV: Oblivion (+mods), The Elder Scrolls V: Skyrim (+mods graphic and quests), Witcher 3:Wild Hunt, Legend of Grimrock - done, Legend of Grimrock II, Gothic (+mods) - done, Gothic 2: Night of the Raven - done, Secret of Mana, Fallout 1, Fallout 2, Star Wars: Knights of the Old Republic (second one too), The Secret of Monkey Island, Chrono Trigger, DEUS EX, Divinity: Original Sin, The Banner Saga

Worth playing:
Iron Storm, Assassin's Creed: Unity, Assassin's Creed: Rogue, The Vanishing of Ethan Carter, To the Moon, Grim Fandango, Grand Theft Auto 5, Tomb Raider, Red Dead Redemption, Middle-Earth: Shadow of Mordor, Transistor, Thief, S.T.A.L.K.E.R.'y (all + mods), Valiant Hearts, Bad Mojo, Crash Bandicoot (1,2,3,4,Twinsanity)

Some of them already done like Elder Scrolls but want to play with mods again.

tl;dr
looking for good PC/X360 games
propose some

Considering that Gothic is the best game out of those, you should probably play all sequels, even the slightly worse newer ones.

Also the Diablos or Path of Exile. Maybe the Dragon Ages although they're less great.

GTA 4,
DayZ Epoch,
Civilization V,
PayDay2,
The Walking Dead 1&2,
Far Cry 3,
Bio Shock Infinite
and Rust

sorry if any of those are already in your list tl;dr