1 and 2 are pretty much the same question.

Hard question actually. I really like all of them. I prefer dungeons with bandits in them. Not Falmer, Draugr, Dwemer Machines, and animal dens.

I prefer nearly everything human.

Me being on the PS3, I have no say for my favorite mod dungeon.

1. Helgen Keep. I like killing the imperial captain and I have restartitis.

2. Valthume. I like visiting my favourite dragon priest.

3. None. Not official content and I play on a xbox.

There's no way I could pick one dungeon.

Blackreach

Pretty much all of the dwemer ruins (Including the ones from Dawnguard and Dragonborn)

Forelhorst

Raven Rock mine

Forgotten Vale is more of an area but I guess you could count it. Same goes for the Soul Cairn.

1 and 2: Forelhost. It's simply the best dungeon in the game!

3 no outstanding modded dungeons..Yet!

For questions 1 and 2 I would say I love all the dungeons. The variety of styles and denizens which inhabit them compliment each other in their differences considering how well done they are in design. They all have plenty of character just like real people and always have a story to tell usually more then one.

As for dungeon mods I haven't really used any. Am very satisfied with the ones in SKYRIM and I have a ton I have yet to explore still. There was one I saw on Youtube some time last year which really caught my eye for its mesmerizing dwemer architecture and mind boggling humongous size. It was like stepping back in time into the golden age of the dwemer.

Blackreach is probably my favorite dungeon. Visually stunning, the sounds in there are awesome, and there's a variety of enemies down there too. There's a giant, falmer, ghosts, spiders, and dwarven machines.

Not to mention its the only place in the game where crimson nirnroot is found.

Valthume. Holiest city of the Reach, for the holiest of Atmorans.

*undead bro hug*

How's my great x50 great grand-daughter doing? Did she conquer Windhelm yet?

Sadly she was killed by Zahkriisos.

That traitorous bastard! First he betrays the cult, then he kills my only surviving kin?!!

Valdar's fault of course.

Kagrenzel. Although a short lived experience, it did a great job with being rather mysterious and unique from other Dwemer ruins, or any other dungeon in general.

The experience was even more frightening considering it was my first encounter with the Falmer.

I have yet to find this place since getting skyrim. And boy have I been looking for it. I heard it was somewhere around riften.

Very hard choice; I might have to vote for Blackreach, as it never fails to amuse.

Normally, though, I tend to get sick of the Betrayed; normally, I prefer hunting vampires or bandits.

Well I don't want to spoil its exact location, but it's quite difficult to find as there is no exact path or road to it. You'll have to do a lot of climbing though. It was just pure luck when I first discovered it.

It's approximately around the borders near Eastmarch and the Rift.

I hate EVERY dungeon where you can find those damn falmer. I also dislike Blackreach in general, it's just boring, Soul Cairn 'cause it's poorly designed, really repetitive and ugly/lore breaking. I also don't really like much the Forgotten Vale area in general because it's too colorful and magic related.

I love all the dwemer ruins, all the places with humans and I love just killing undead. But the dwemer ruins are the best! Unfortunately, falmer are too common in those. I really hate them. I love the idea of Snow Elves but I just hate Falmer as much as I hate Chaurus.

But everything is white. Even Skyrim has more color.

I don't know.. I just don't like it..

1 & 2 Forelhost, Because it's a very neat Dungeon and my characters alway's have to be careful or they get their butts handed to them, reguardless of lvl ( I rarely get above, 50). I usually try and find a good RP reason for my characters to do that dungeon... just because.

360 so no mods