Buy the entirety of Riften. Like Maven. Except buy her out too.

Retire in a nice home.
join the Bards College, they have some things they would like for you to get back for them.
break into palaces and other rich area and rob them blind.

then start a new and different character.

You have 100k and only bought one house and all the upgrades? I own all homes and all upgrades, plus another 100k... Now that is rich!

If you don't leave a trail of guards with their throats slit to lead the owner to his empty treasure chest, it's just not worth it.

EDIT: Oh yeah, stuff for you to do. Do what all proper adventurers do, spend it on ale and Noble Seamtresses.

Try something new. Bethesda has given you endless possibilities in this game.

Take up crafting, mining, picking flowers. Become a treasure hunter or try to assassinate every NPC in Whiterun.

I am amazed that with such an open-ended game that anyone would get bored or at a loss for things to do.

Perhaps, take a week off and come back to a fresh Skyrim.

Sounds like a trap. Do what all rich people do.

Get richer.

Share the gold with your companion or something.

Now be charitable

I've noticed shop and home shelf objects don't seem to respawn. NPCs don't react to having been robbed blind (and pantless). They don't change locks, they don't investigate or increase patrols, they don't hire mercenary guards... But they do magically know to send hired thugs after you. Of course then you can never confront them on it.

Lockpicking is broken and needs an overhaul, as well.

I'm picky about it though, i doubt most people are bothered by many of these issues.

If you do all the thief like things: the Guild Quest, the trinkets for Delvin, the Stones, all the heist/burglary/sweep/etc side quests - how long is that? I'm doing more or less the same right now, but am doing assassin and daedric quests too, but it seems like the thief stuff alone would be ~20-30 hours.

join the Republican Party?

If I had a a 100k, I would use it to buy stuff like books, jewelry, training, food, exotic potions, ingredients, soul gems, arrows, ingots. There are plenty of ways to spend and make money.

A true thief or merchant steals or buys somethings of great value and holds on to it as their trophy.

Fill your house with stuff. Trinkets, rubies, garnets, clothes. Whaterver. Find the uniqe stuff and store it in your home.

Break into people's houses, steal small trinkets and stick them in other people's pockets.

Steal all the weapons from the guards of the cities opposing the faction you've sided with.

Continue your career of thievery, but start leaving behind flawless rubies as calling cards.

Start drinking, in amounts that would make even a Nord say "Dude, that's a bit much, isn't it?"

Buy all the available houses in every City. Decorate them with your ill gotten gains.

Join a side in the War, steal all their weapons and armor, and watch them march to a certain doom.

Pickpocket a Dragon Priest and steal his Mask.

Pickpocket a Dragon.

Pickpocket the clothing from Ulfric Stormcloak and General Tullius, and swap them.

Sit back and marvel how none of this affects the game world in any way whatsoever.

That has to be the best idea I've ever heard.

What else is money for? BUY BUY BUY

LOL Well said.

Totally doing this.

OMG..............classic. LOL

I wonder if that's even possible??................that would be a great challenge.

Buy a Squidbear and ride it to [censored]in Sovngarde.

If this was an mmo it would be time to corner the market and make the poor pay more for bread.

Not 100%, some are quest related and therefore immortal.

there's 150 unique dungeons many filled with possible unique treasures

so do that...

or alternatively make a Scrooge McDuck room and swim in your treasure...

Can't be done, surely? Aren't their clothes hard-coded unless you kill them?