Gold ingots, skulls, and every readable parchment/book.

wooden spoons...lots and lots of them...

With my main character, dragon parts, black soul gems (unused), amethysts, garnets, rubies, sapphires, and Orcish swords/waraxes.

With my third character, flowers. All flowers must be picked and scattered in the Companions' living quarters.

When I get around to making my evil character, it'll be all ruined and burned books

For some reason, I really love this.

Those swirling power sources you pick up from those giant Dwemer Metal Guardians you find in Dwemer ruins. No idea if they have any actual practical use, but I've got quite a few of them now.

Being that my character is based on Puss in Boots, I collect boots. I wish I could display them proudly, but Skyrim's physics are so borked things never stay where I place them, so for now they all sit in a chest, waiting for the day Bethesda fixes the game so I can decorate properly.

Dwemer-related materials. Especially the books, Love reading about them and their History.

...Dibella statues

Claws, books, insects, armor sets, cool weapons, amulets of the devines... Woah, I'm kind of a collector actually. Everything is appropiately displayed in my awesome Windhelm house.

Dwemer Parts..well anything Dwemer really.

No really I upgraded my house, took -EVERYTHING- that wasn't Dwemer/nailed down and put it in a corner/fire pit, I then put dwemer plates, shields, parts etc etc all over the house. I made Dwemer Tables (METICULOSULY), my Mannequins wear Dwemer stuff, Various enchanted Dwemer weapons mounted everywhere, spawned a Sphere and several spiders, Killed them and Placed them in the house.

Made Dwemer Chairs out of Dwemer ignots.




yeah...

Anything Dwemer for me. Books I love books. Any alchemy ingredients I pick up. Um keys see anything rare or valuable. For some reason I find myself keeping all of the dragon bones and scales I get.

I collect books. I aim to own a copy of every single book in the game. The only rule being that I am not allowed to steal them, unless they are very rare and stealing is my only choice.

I also have a "Treasure Chest" which is full of various gems, ingots, jewellery and a Dibella Statue. I would love to have these on display but there is nowhere suitable. I miss the hidden treasure room in Battlehorn Castle in Oblivion.

I'm also a bit of a wine enthusiast, although there is not many varieties to choose from. I probably have in excess of 100 bottles!

Arrows, I don't like collecting them, but my knee does

Cheers

One of every kind of shield, and one of every kind of helmet. They would be great for decorating the house if I could only place the dang things right. (would love to have a mod to hang shields on my walls)

Storm

BOOKS.

I save / collect Tankards / Flagons. After I clear out a place of monsters, mobs and people. I go back through and collect every Tankard or Flagon that I can find. I bring them all back to Whiterun, which very often requires a few trips to get them all. Once back in Whiterun, I drop them, singularly, one at a time, in front of the door of the House of Gray-Mane. At first the Gray-Mane's just seemed annoyed. Now, I am level 60, 50+ hours into the game and they can not get near the door of their house. Very often, I will find Avulstein, Eorlund and Olfina (I think) vibrating / shaking / spazzing out, trying to wade through the mountain of Tankards blocking their doorway.

arrows i'm a mage i have no use for them i just end up having them i thought it was an arrows to the knee didn't ya i use to but then i was introduced to a giants club

Dragon souls and levels.

Stones of Barenz- oh no wait.

Enchanted weapons, or just weapons in sets, on the shield mounts I have Falmer shields, with a sword and an axe behind it, and some Forsworn stuff. my Winterhold house has loads of them on the walls and in the cases, and armour sets as well, I put Cicero's clothes on a Mannequin, and the Emporers too, and the third one was for a Forsworn guy, it's a shame the other houses don't have much of an armory. I love arranging everything.