It's the best Indy one-man isometric RPG that I know of.
But in terms of scale RPGs we have New Vegas & DLC, Mass Effect 1, Dragon Age Origins & DLC, Baldur's Gate 1 & 2, Planescape Torment, Knights of the Old Republic 1 & 2, Jade Empire. And if you mod it up, Temple of Elemental Evil is now pretty amazing too. There are some amazing Dungeon Keeper style games too; Bards Tale IV, Grimrock 1 & 2, The Quest, Moonshades, etc.
Fallout is one of the "tier zero" rpgs, not only fun and interesting but also set the bar incredibly high regarding quest design and puts to shame most quest writing in modern rpgs(including EK). It was a milestone in originality, extremely influential to the genre and you can't compare it to any others in the list, IMHO. Its influence is not just about its own Fallout franchise, but about how it was the true precursor for the Infinity Engine games like BG or PS:T. And because everyone writing a quest in the following decades would directly or indirectly be measured against the standards set by Fallout.
Being older, maybe Wasteland comes close and can be considered a precursor of Fallout, but mechanically it was derivative of Wizardry and it was not to influential so I'd put it in "tier 1".
Update: I found Exiled Kingdoms on Google Play. There are also many other rpgs on that platform, like Overlive, a zombie apocalypse rpg (you should play Overlive, but, it is based on text instead of visuals, but the game is very good!)
Anyway, there are many other games that i should add to the poll.
See more answers soon!
If i can find a way to...
Well of course the original Fallout developers went on to make Planescape Torment, Icewind Dale, Dark Alliance II, KOTOR Sith Lords, New Vegas, Stick of Truth, Pillars of Eternity, Tyranny, The Outer Worlds...
... it's amazing how many of the classic western RPGs came out of basically two sets of developers who also strongly cooperated with each other: Obsidian/Black Isle, and BioWare.
I like VDX's Newest reply.
Yes, gameplay is a personal expirence, so if you want to, if you have the "other" vote, you can put your answer in the commenting section. Also if you want to, you can put your top 5 or top 10 favorite RPGs on this thread.
Gameplay-wise the freedom for doing anything, and I mean either being an saint or a heartless backstabber, makes the whole difference for me. It can turn even shallow-plotted and bad combat games, such as Skyrim, into something I play for hundreds of hours.
Earlier on there were some harsh limitations on developing interactive open world games. Nowadays, with all the fresh computational resources and experience of the industry, I'm hopeful that indie companies can make games that are just as amazing as some cited here.
Also, I'd add Divine Divinity as a RPG worth playing as well.