A challenge? Well I suppose that's one way to describe it. Chaos Strikes Back is so hard it actually hates you.
Dungeon Master 2 was very meh. I suppose it's worth playing for completeness but the game is so damn dull. It's like they identified everything good about Dungeon Master and carefully extracted them. Like Eye of the Beholder 3 in fact.
One of the best dungeon crawlers was in fact Shining: The Holy Ark. If Sega ever port that it will be an instabuy for me. Another port this time from the Amiga would be Raven software's Black Crypt.
Oh and the original Bards Tale games.

No problem :)

My favorites are
Lands of Lore: Throne of Chaos (you get an automap early on though, unless you mess up and miss it)
Eye of the Beholder 2

No one's mentioned this yet, and it's not really true 3D but, one of my favorite series is the Bard's Tale. I've still got my hand drawn maps.
The remake of a couple of years ago included a pleasant surprise bonus of the three original BTs (fantastic fantastic fantastic games if you've not played them [or even if you have]). The only problem is that I've not been able to install them on Vista (and haven't tried on Win 7 yet).
There's also a fan made game based on the originals called Devil Whiskey [url=]http://www.devilwhiskey.com/main.html[/url].

My favourites were Dungeon Master, Bloodwych and Captive (futuristic dungeon-crawling),
I also liked Lands of Lore, and the Eye of the Beholder series.
Was Xenomorph a dungeon-crawler too? I always wanted to play that game, but never managed to get a copy.
I really want to play Captive again now...

The Eye of the Beholder series. Good stuff imho.

Oops - I need to read the posts more carefully :-/

I want to play again Bloodwych, Dungeon Master I & II, and Eye of the Beholder series.

It would be amazing it appeared on GoG.

Wizardry: Tale of the Forsaken Land is pretty cool.

Might and Magic I and II were fantastic. MM2 does auto-map, but it is pretty basic.
You had to map in Wizardry as well. I shudder to think of how many hours I
Logged playing the Might and Magic series. Great character classes and by the time
You got to the end they were epic. Fun story line to boot.

Obviously the Necromancer class is pretty popular for these dungeon crawlers :D

If you didn't know about "DM Java", I assume you don't know DM Return to Chaos either? It's a faithful windows freeware clone of DM and DM 2, looking just like the originals, and also including a level editor and a custom campaign.



@OP:

Keep an eye out for the upcoming Legend of Grimrock indie dungeon crawler.

If "party" is a must, the "Lands of Lore" series and "Anvil of Dawn" do not fit the description because you only play one character. However, if you don't mind that and neither the auto-mapping, they're all very good 3D dungeon crawlers. Stonekeep is another nice 3D solo dungeoon crawler with 90 degree 'block' movement (graphically less attractive than its older cousins but still good).

And yeah, EOB rocks.

My favorites would be Lands of Lore 1, Eye of the Beholder 2, and Might & Magic 6.

I enjoyed Strange Journey for the DS.

The dungeons however, could be a bitch to navigate.