Must-Play Games? Which are the True Gems?

Portal 2

I haven't played many games so I can't advise you too much but i see quite a few so called gems

The only games I have played in your list are
Grand Theft Auto: San Andreas which I played on playstation which I loved as had a love for the earlier games in the series worth playing through at some point man didn't find it that all that challenging though but good fun
& the other game is Portal which is short and a must play man, in my mind, epic puzzle game with good humour in it

Deus Ex Human Revolution and the original both warrant playthroughs, and are both incredibly good in their own right, Postal 2 is one of the most fun games of all time, and can easily just be played in short bursts, and Shadow Warrior is a great classic style fps that beats any other one released recently.

Assassin's Creed (at least first one)
Borderlands 1&2
Call of Juarez Gunslinger
Deus Ex Human Revolution
Dishonored
F.E.A.R
Fallout 3
Far Cry 2&3 (I haven't played first one but second and third are great games)
Fuel (some hate it, some love it)
Oh god, GTA 3 and Vice City are "must play"
Hitman series
Metro 2033 and Last Light
Both Portal's
Both The Witcher's (again, some may love it, some may hate it)

From outside your list...depends what u like. I would recommend Superbrothers: Sword and Sworcery, S.T.A.L.K.E.R series, Diablo 1 and 2, Torchlight 1 and 2, Dark Sector, World of Goo, Call of Juarez and Call of Juarez: Bound in Blood...and probably many more :)

Arma Cold War Assault is very old but it's the best game you have out there if you ask me. The learning curve is high (it's not a forgiving arcade shooter but a real simulation like the ARMA serie) and rewarding. Same learning curve can be said for Mount & Blade Warband. Others I spotted are Assassin's Creed 2, Arkham Asylum and Arkham City, Deus Ex, Dishonored, the Half-Life 2 and the Portal serie and Rainbow Six 3 Athena. You have some very nice quality games there.

Grab The Swapper on humblebundle. Best graphic, intriguing story with ambient music plus great puzzles with solutions posted everywhere on youtube if you got stuck. If you got tired killing stuff in video games and just want something relaxing, this is certainly a game you must play.

I think it would be helpful if you post what types of games you enjoy. I can recommend a great number of games that I like, but just because they appeal to me doesn't mean they'll appeal to you.

Here are some games from your collection that you've played less than 2 hours of and that I enjoyed:
XCOM: Enemy Unknown
The Witcher (1 and 2)
The Stanley Parable
Spec Ops: The Line
Civ V
Natural Selection 2
Mount and Blade: Warband
Deus Ex (HR and the original are both good)
Hotline Miami
FTL

Civilization V, Garry's mod, GTA III, GTA VC, Arma 2, Half Life 2, all Hitmans, Metro 2033, Metro Last Light, both Trines

Narcissu,because I personally think everyone has to at least try a vn once.

I think everone should play Mafia 1, Portal 2, Mass Effect 1-3, Max Payne 2-3 (haven't played the first one, people say it's very good as well) at least once.

I like those :P

L.A. Noire

Borderlands

Assassin's Creed

Age of Empires® III: Complete Collection

Arma 2

BioShock Infinite

Company of Heroes

DiRT 3

Fallout: New Vegas

Far Cry® 3 Blood Dragon

Half-Life 2

Mafia II

Max Payne

RAGE

System Shock 2

The Witcher 2: Assassins of Kings Enhanced Edition

Tom Clancy's Rainbow Six 3: Gold Edition

Trine 2

XCOM: Enemy Unknown

If total mods count (and you like being scared), Nightmare House 2 is definitely worth a look. It feels like something Valve made, with its humor and interesting storyline.
I'm also quite fond of the Bioshock series and, of course, the Portal games!
(Spaaace)

Grand Theft Auto IV, Max Payne 2 The Fall of Max Payne, Severance Blade of Darkness, Prince of Persia Sands of Time, Assassin's Creed 2, Splinter Cell Chaos Theory, Thief Deadly Shadows, Hitman Blood Money, Dishonored, Dead Space 2, Mass Effect, Neverwinter Nights, Torchlight 2, S.T.A.L.K.E.R. - Shadow of Chernobyl, Metro Last Light, Unreal II The Awakening, Bioshock and Bioshock Infinite, Half Life 2, F.E.A.R(THE FIRST ONE ONLY), Return to Castle Wolfenstein, Call of Duty 2(back when the series was good), Medal of Honor Allied Assault, Crysis, Far Cry 3, Deus Ex(Human Revolutions's nice and all, but if we're talking about gems, the first one is the one you NEED to play) Red Alert 2, World in Conflict, Heroes of Might and Magic 3, Rome: Total War, World of Goo, Mark of the Ninja, League of Legends, Need for Speed Underground 2. There, I think I covered all of the brilliant games from all of the genres I play. Since I don't play adventure games and simulators, you'll have to ask someone else about the best from those categories.

Borderlands 1-2. Those games have blown me away! They are so characteristic, humorous, unique, with comic-style eye candy graphics and real-life relations, I LOVE THEM SO MUCH, and with the GOTY versions, I just can't stop playing!

Other favourites of mine were Fallout 3 & New Vegas, for some reason I can't get myself to suffer with the first 2 & Tactics. Not for me... :(

And then... Portal, Portal 2. Those speak for themselves.

As of indie: Machinarium is a MUST! Or any Amanita game, but Machinarium is the best indie. You can really feel the agaric mushroom effect. :)))

Zzzzzzzzzzzzzzzzeldaaaaaaaa!

"Unfortunately, I recently have come to see that I have less and less time to play games nowadays, ..."

Welcome to adult life. Later on, school will be replaced by kids and family. You can expect your gaming time to be limited (and usually scheduled in advance) for the foreseeable future. I recommend you start focusing on games you can play for about half an hour at a time before saving and/or quitting.

Silent Hill 2

Gems ?

Dwarf Fortress, Arcanum, War In The Pacific Admiral Edition ( but that one can take a year to finish ), Command Air Naval Operations, Dominions 4, those ones are all gems imho.

Planescape: Torment
Baldur's Gate 1&2
Europa Universalis IV (strategy)

I'm amazed no one mentioned Psychonauts yet. It was one of the best games I played in years. A really undervalued Gem.

GZB72-ADEYK-ER3V9

1. Just Cause 2 for open world free roam sandbox madness. And it has a multiplayer mod, too. It's perfect if you just want to launch a game, have some fun in a 400 square miles tropical island, and then stop playing whenever you want.
2. Trine/Trine 2 if you enjoy side scrolling puzzle/platformer with wonderful graphics and amazing soundtracks.
3. Half-Life 2... Because it's an entirely different kind of shooter.
4. Left 4 Dead 2. Maybe not a gem, but it's the best zombie killing game around, if you enjoy that kind of stuff.
5. Skyrim, of course. because it is the most complex world I've ever seen.
6. Tomb Raider (2013). You want a hidden gem? Here you go. Amazing game, worth a try.

I won't include it in the list, but I personally really enjoyed Mafia II. The story is excellent, and the game itself is really great. I think it's highly underrated, unfortunately.

1. Assassin's Creed series
2. Batman series
3. Deus Ex series
4. Thief series
5. The Witcher series
6. Civ V

Skyrim
Silent Hill 1