Things I generally tend to amass and use wealth for:
-The Vvardenfell Travel Agency rings are around 8000 each for a character with low to medium Personality and Mercantile skills, but I want them as soon as possible because they're among the more immersive fast-travel options available.
-Non-default clothes, armor and weapons. I'm talking about style motive, of course; I like both my female characters and their male companions to have spiffy outfits, and that means a lot of expensive trips to the Metal Queen Boutique, Slof's Goth Shop, and a bunch of other shop mods for Better Bodies. Not everyone is as into dressing up their characters, of course. But if you've got expanded Balmora there's a very nice weapons shop with particle and glow-mapped awesome-looking weapons that are very worthy of your attention. The Kat's Kastle mod has some nice furniture, pets and other goodies upon which to spend money, too (although I've also used it as a money tree during that "pauper phase" early in game since you can get a lot of freebie dresses worth 2000 each).
-Enchanting. Unless your character is an enchant specialist, it's quite easy to drop 60k on one weapon. And the serious adventurer will want a LOT of enchanted items, especially if you're using a mod like NightVeil that basically requires you to have one for each elemental weakness (fire, frost, shock). (I never got that one to work for me owing to a dialogue bug it seems to have, but I did read the whole readme before I deleted it.
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-Blood shots for Johnny (or Synda, if you're playing a guy) from Qarl's Underground mod. They are 8000 each. After a while I got tired of watching the vampire bitey animation (it clips kind of badly and Johnny will trigger it at inconvenient times).
-Training in rare or minor skills. In particular, there's a guy you have to kill for a Fighter's Guild quest who will train in marksman if you're a Thieves Guild member. I therefore spent several thousand getting all his training before I killed him.