I don't really use dungeons and almost never have. Sometimes the location the encounter is based on will be an old ruin or cave system, but the location itself is more set dressing than anything. So if the group is tracking down the BBEG to his lair, technically that lair could be considered by some people to be a dungeon, but to me that doesn't qualify it as a dungeon crawl.
I equate dungeon crawls with an old school labyrinth of loosely connected rooms with sometimes tenuous connection to logic. The setting is pretty much fixed, you're just exploring to find out what's there. Sometimes you have a goal in mind (find Bob the Bugbear) usually it's just kill everything and loot the corpses. They can be fun in their own way, and have a certain old school charm. I just know I'm not very good at running them so I don't. I certainly wouldn't want a steady diet of it.
With that and apologies to Sir Mix-A-Lot
Oh, my, gods Becky, look at this dungeon
It is so big, it looks like
One of those old dungeon crawls.
But, ya know, who understands those adventurer types?
They only delve in it, because,
They're looking for gold and XP, 'kay?
I mean, this dungeon, is just so big
I can't believe it's just so complex, it makes no sense
I mean gross, look
It's just so, old school
I like dungeon crawls and I can not lie
You other adventurers can't deny
That when a DM pull out that big grid diagram
And a treasure map in your face
You get sprung, want to pull up tough
'Cause you notice that dungeon is stuffed
Deep in the depths it's hidden
I'm hooked and I can't stop staring
Oh DM, I want to get explorin'
And make some maps
My homeboys tried to warn me
But with that map you got makes (me so greedy)