Eye Of The Beholder 1-3. Dungeonmaster, Dungeonmaster II, Black Crypt.
Oldschool-styled but new: Legend of Grimrock 1-2.
LoG is really excellent, captures the jump-scares of the old school Dungeonmaster-styled games :)
There's Bard's Tales, Might & Magics, and so many more.
Of course like Eye of the Beholders and some others, they are still not even re-released (yet).
Some lucky bastards have them on Amiga emulators :p

Icewind Dale might be what you're looking for. Not too filled with lore, but still a good story and good game.

Oldschool games were text-heavy. I prefer that style, but it can be irritating for people who don't.

Not on GOG but the first 2 TES games - Arena and Daggerfall are freeware these days, fans have packaged them up so you don't have to mess with DOSBox too much - I'll dig out the link if you're interested...

Anvil of Dawn
Krondor/Antara series
Wizardry 6-8
Wasteland 1

If you need more, i'm happy to oblige.:)

I was wondering when someone was going to suggest Anvil Of Dawn...

That's good to know.

That's not true actually, even if my slightly snarky representations of JRPGs suggested that this is the case. I have nothing against a lot of text as long as it's well made and not just wasting your time. The same goes for puzzle solving. For instance the dialogue in Ultima Underworld (which I watched, didn't play) is well-made and doesn't insult your intelligence with being overly pompous and self-important.

Thanks for all your concrete suggestions. I will probably check out some LPs of the games you mentioned to see if it appeals, and either replay Fallout 1 or go for broke and just play whatever sparks my interest. After all, there is only one rule for a successful let's play, that is to enjoy yourself.

Worlds of Ultima - The Savage Empire &
Ultima - Worlds of Adventure 2: Martian Dreams

The Ultima games in general tend to be fairly forgiving in terms of gameplay & difficulty. It's usually more the world itself that's fairly complex. These two spin-offs of the main series streamline things even further (for example, the magic system in Savage Empire is significantly more simplistic than in Ultima VI) and feature really fresh and compelling RPG scenarios.
Also, they're free.

Anachronox

Basically a JRPG in the style of Final Fantasy VII, but made by American developers as a Cyberpunk/Space Opera/Fantasy/Comedy epic. Seriously, this is a hilarious game.

And since Fever_Discordia mentioned them, here are the links to the fan-made installers for the freeware Elder Scrolls games:
The Elder Scrolls - Arena
The Elder Scrolls Chapter II - Daggerfall

Arena in particular is a lot like the classic dungeon crawlers.

Note: While the installers are really nice, both of them cofigure DOSbox with wrong cycle settings. Arena will run slow and choppy, while Daggerfall will have completely broken movement on faster computers. To fix this, you'll have to go to the .conf file for each installation and correct that setting.
For Arena, it should be: cycles=max
For Daggerfall, it should be: cycles= fixed 50000

In case you're interested, I've decided now to start a let's play of Fallout 1. Had some slight issue recording this game, but now it seems to work fine (in short: Dxtory > Fraps). After that I'll probably do Fallout 2, or maybe even Wasteland 1. The latter seems indeed very playable still, and also quite hilarious.
Also Anvil of Dawn looks great, and I still have that dream in my head of doing the whole Ultima series (starting from iv), but we'll see. Anyway, thanks for all your suggestions, you really inspired me to discover the role playing genre.