Top 20 Western RPGs of All Time for PC (with a download link), only recent games (after the year 1999) available on PC are present in this list (until 03/2016)
NOTE: this is just a subjective not exhaustive list.

20. Planescape : Torment

Sigil… A place with gates that lead anywhere in existence, provided you have the proper key. It is a neutral ground and a watering hole for races across the multiverse, all under the watchful shadow of the Lady of Pain, the enigmatic ruler of the city. It is a place where the word is mightier than the sword, where thought defines reality, where belief has the power to reshape worlds and change the laws of physics…

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19. Gothic

War has been waged across the kingdom of Myrtana. Orcish hordes invaded human territory and the king of the land needed a lot of ore to forge enough weapons, should his army stand against this threat. Whoever breaks the law in these darkest of times is sentenced to serve in the giant penal colony of Khorinis, mining the so much needed…

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19. Fable : The Lost Chapters

Each person you aid, each flower you crush, and each creature you slay will change this world forever. Fable: Who will you be?

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18. The Witcher 2: Assassins of Kings

Enjoy a captivating story, dynamic combat system and beautiful graphics in the second installment in the RPG saga about the Witcher, Geralt of Rivia.

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17. Deus Ex

The year is 2052 and the world is a dangerous and chaotic place. Terrorists operate openly – killing thousands; drugs, disease and pollution kill even more. The world’s economies are close to collapse and the gap between the insanely wealthy and the desperately poor grows ever wider.

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16. Fallout: New Vegas

Welcome to Vegas. New Vegas.
It’s the kind of town where you dig your own grave prior to being shot in the head and left for dead…and that’s before things really get ugly. It’s a town of dreamers and desperados being torn apart by warring factions vying for complete control of this desert oasis. It’s a place where the right kind of person with the right kind of weaponry can really make a name for themselves, and make more than an enemy or two along the way.

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15. The Elder Scrolls III: Morrowind

The Elder Scrolls III: Morrowind® Game of the Year Edition includes Morrowind plus all of the content from the Bloodmoon and Tribunal expansions. The original Mod Construction Set is not included in this package. An epic, open-ended single-player RPG, Morrowind allows you to create and play any kind of character imaginable.

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14. Deus Ex : Human Revolution

You play Adam Jensen, an ex-SWAT specialist who’s been handpicked to oversee the defensive needs of one of America’s most experimental biotechnology firms. Your job is to safeguard company secrets, but when a black ops team breaks in and kills the very scientists you were hired to protect, everything you thought you knew about your job…

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13. Torchlight II

The award-winning action RPG is back, bigger and better than ever! Torchlight II takes you back into the quirky, fast-paced world of bloodthirsty monsters, bountiful treasures, and sinister secrets – and, once again, the fate of the world is in your hands!

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12. The Elder Scrolls IV: Oblivion

The Elder Scrolls IV: Oblivion® Game of the Year Edition presents one of the best RPGs of all time like never before. Step inside the most richly detailed and vibrant game-world ever created. With a powerful combination of freeform gameplay and unprecedented graphics, you can unravel the main quest at your own pace or explore the vast…

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11. Mass Effect

As Commander Shepard, you lead an elite squad on a heroic, action-packed adventure throughout the galaxy. Discover the imminent danger from an ancient threat and battle the traitorous Saren and his deadly army to save civilization. The fate of all life depends on your actions!

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10. Star Wars : Knights of the Old Republic

Choose Your Path. It is four thousand years before the Galactic Empire and hundreds of Jedi Knights have fallen in battle against the ruthless Sith. You are the last hope of the Jedi Order. Can you master the awesome power of the Force on your quest to save the Republic? Or will you fall to the lure of the dark side?

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9. Neverwinter Nights

Experience one of the most popular role-playing adventures of our time, a journey that has thrilled millions. Inhabit dreamlike worlds of myth and mystery. Boundless lands of deadly creatures, foreboding omens and bold heroism.

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8. Baldur’s Gate II : Shadows of Amn

An epic continuation of the story that began in “Baldur’s Gate,” this RPG is set along the southern portion of the Sword Coast, a detailed and rich area of the Forgotten Realms called Amn. It features 300 spells and 130-plus monster types compared to only 130 spells and 60 monster types in Baldur’s Gate

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7. Diablo II

In Diablo II, return to a world of dark fantasy. As one of five distinct character types, explore the world of Diablo II — journey across distant lands, fight new villains, discover new treasures, and uncover ancient mysteries, all in the quest to stop the Lord Of Terror, once and for all.

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5. Dragon Age : Origins

You are a Grey Warden, one of the last of a legendary order of guardians. With the return of an ancient foe and the kingdom engulfed in civil war, you have been chosen by fate to unite the shattered lands and slay the archdemon once and for all.

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4. Mass Effect 2

Recruit. Explore. Control.Two years after Commander Shepard repelled invading Reapers bent on the destruction of organic life, a mysterious new enemy has emerged. On the fringes of known space, something is silently abducting entire human colonies.

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3. The Witcher 3 : Wild Hunt

The Witcher is a story-driven, next-generation open world role-playing game, set in a visually stunning fantasy universe, full of meaningful choices and impactful consequences. In The Witcher, you play as Geralt of Rivia, a monster hunter tasked with finding a child from an ancient prophecy.

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2. The Elder Scrolls V: Skyrim

EPIC FANTASY REBORN The next chapter in the highly anticipated Elder Scrolls saga arrives from the makers of the 2006 and 2008 Games of the Year, Bethesda Game Studios. Skyrim reimagines and revolutionizes the open-world fantasy epic, bringing to life a complete virtual world open for you to explore any way you choose.

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1. Fallout 3

Prepare for the Future™ With Fallout 3: Game of the Year Edition, experience the most acclaimed game of 2008 like never before. Create a character of your choosing and descend into an awe-inspiring, post-apocalyptic world where every minute is a fight for survival.

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