Best system for Dungeon Crawling

[Libramarian]

Moldvay Basic with AD&D 1e monsters and magic items.

 

[the_redbeard]

I think the key to answering this question is what the OP means by a dungeon crawl?

4e is excellent for set piece encounters. WotC looked at how people were playing 3.x, saw that most of the session time was spent on encounters, and then engineered 4e around that.

So if you think of a dungeon crawl as encounter to encounter followed by a boss at the end, then 4e is a fine choice. I'd even recommend it for that.

However, when I think of a dungeon crawl, the pillar of the game that I think of is exploration. Avoiding hazards, negotiating with monster factions, puzzle solving, carefully scouting areas to avoid monsters to find the objective: treasure.

5e is the best of the WotC versions of DnD for that. But B/X (and there's a new, pared down version of B/X called B/X Essentials on rpgnow), Basic Fantasy and such are maybe better.