UPDATE: This sale has now finished and is no longer valid. However, I will leave this list up and intact to be used as a more general recommendation guide. Each game on this list is worth buying in my opinion and although they won't be discounted anymore, my comments on them still stand.
Today is the final day of the Steam Summer Sale which has just as many absurd discounts as ever. This post is my list of the very best RPG games to pick up before the discounts wear off. I will give a brief overview of my thoughts but for in depth exploration of the games themselves, I encourage you to do some research and read or watch some reviews to see if the game is the type you enjoy. All games here are RPGs but there is such variation in the overarching genre that it is always worth finding out as much as possible before buying.
The list
Dark Souls III - The third entry in the Dark Souls series continues the legacy of difficult but satisfying gameplay and was a commercial and critical success. The base game is available today for £9.99 and you can get the deluxe edition to include all DLC for an additional £8. Each DLC is not discounted and is expensive on its own, so if you expect to enjoy this game then I would recommend going for the deluxe edition for £17.99 so you don't miss out on the DLC discount.
Darkest Dungeon - This dark and grim dungeon crawler is a stand out in its field. It toys uniquely with issues such as the mental and psychological health of your party members to give it a different spin than other dungeon crawlers. Recent reviews have been negative but only due to an issue with the Korean translation, not with the game itself so don't be put off by the 'mixed' recent reviews. £5.69 is a really good deal for an original and compelling RPG.
Deus Ex: Human Revolution - Director's Cut - The original Deus Ex is a legendary title in the RPG world for its huge number of gameplay possibilities and permutations. While Human Revolution doesn't quite reach the heights of being a yardstick for other RPGs in the way the first game did, it is certainly still a compelling and interesting sci-fi game with plenty of options and an interesting story. Best of all, the price is absurd at £1.94. It is nice to have a coffee from a cafe every now and then but this game being cheaper than a single coffee is a genuine bargain.
The Divinity series - Being midway through playing Divinity: Original Sin means I can wholeheartedly recommend what I've played so far as a deeply engaging CRPG. A 70% discount means you can pick it up for £8.99 today and its sequel is by all accounts even better. At £23.99, Original Sin 2 is a bit more expensive but the prospect of getting both games for £33 is truly enticing and will provide many hours of gameplay for less than the price of a single new AAA release. The previous Divinity series entry are also cheap, with all previous series titles available for £2.29, a 90% discount.
Dying Light - A multiplayer friendly zombie RPG first-person shooter with free-running and amazing dropkicks sounds pretty fun on paper and Dying Light absolutely delivers. The carnage of ragdoll physics combined with punchy combat and full parkour mechanics makes for compelling gameplay alone, but add in two or three friends and there is a huge amount of fun to be had. Tense, funny and with a fantastic team of developers behind it, Dying Light is well worth picking up and the excellent driving based DLC The Following is well worth paying an extra three pounds for the Enhanced Edition, which will cost you £13.19. A solid recommendation for this one.
The Fallout series - Every Fallout game is available on Steam and is discounted in this sale. The first and second in the series are old-school CRPG's and each from Fallout 3 onward is in the first person 3D Elder Scrolls style. All are worth playing though be aware that the 3D PC versions before Fallout 4 are highly prone to bugs and can be finicky to play. Fallout 4 Game of the Year edition is my best value for money recommendation at £19.99 but if you can get it working and are confident modding, the Fallout: New Vegas Ultimate bundle for £7.49 is a better game in terms of quality.
Final Fantasy XV - My review for this game is on the way but suffice to say it is well worth the full base price I paid when it was released, so to recommend it at half price for £17.49 is a complete no-brainer. The Windows Edition which is on Steam contains the three superb DLC mini-expansions that explore stories for each of the three supporting party members from the main game. Having only played this entry, it is the only one I will recommend specifically but the entire Final Fantasy series on Steam is also enjoying discounts, including the classic Final Fantasy VII.
Kingdom Come: Deliverance - After a rocky start with widespread bug reports, Kingdom Come has revived itself with a number of patches and additional features. An upcoming DLC also makes this an enticing long term game for those of you looking to find one game to lose yourself in. Playing as Henry, a random peasant, this game is about the everyday survival in medieval times and rather than being a destined hero bound for greatness, Henry is just trying to make do and get on with his life. Addition of a hardcore mode in a recent free update has also improved the realism and difficulty of the game. At £27.99, this is most expensive title on the list but is also the newest. If you enjoy realism and the true roots of role-playing, this game will scratch your itch.
Mount and Blade: Warband - Aside from Skyrim across the base and special editions, Warband is the game I have spent the longest playing on Steam at 175 hours. I know that's a poor show compared to some wizards with 500+ hours in a variety of games but I tend to spread my time out, which shows how much fun Warband can be. Combining a weighty first or third person combat system with a plethora or stats, traits and abilities with a fully immersive and engrossing kingdom management campaign is difficult, but Warband manages both and piles plenty of other features on top. Add to this one of the most active and passionate modding scenes on PC and you have a recipe for an incredible RPG experience. It is a dated game by now and can feel and look more than a little clunky, but it still holds up as a magnificent achievement in player agency. £7.49 to include the Viking Conquest campaign is well worth the price, but you will still never run out of things to do by getting the base game for £3.74 and playing around with some mods. Highly recommended and reliving this is making me extremely excited for the next Mount and Blade game; Bannerlord, which is deep into development at the moment.
The Witcher series - The Witcher 3 Game of the Year edition includes the base game as well as both expansions. Each expansion is a huge addition and to get all three for £13.99 is ridiculous in terms of value for money. The other two games in the series are also discounted heavily and the total cost for all three will be £17.27. The Witcher 3 Game of the Year edition is my single biggest recommendation as the quality and quantity of content you get for its price is unmatched by the rest of this list.
Highest recommendation
The Witcher 3 is for me, the best RPG ever made and it wins my best recommendation, followed by Mount and Blade: Warband (assuming you are comfortable with modding).
This list is a subjective list of those I consider to be the best and those I know to be good value. There are an enormous number of other games on sale and a huge number of RPGs that I haven't mentioned so if you are looking for some new titles, do have a search around and find some that suit you. There are plenty of options!