The only really expensive items in the game are the houses that you can purchase and upgrade in the major holds. Even if you haven't purchased any of them yet, your 75,000 in gold is plenty to buy them all.
Have you purchased all the spells that you want from the teachers at the Mage's College? Again, you'll come nowhere close to burning through 75K of gold.
Finally, having a decent chunk of gold is useful as an investment fund for leveling your smithing/enchanting. You can buy large amounts of animal skins, iron ingots, soul gems, etc. Craft a bunch of equipment and throw enchantments on them to level up. In the vanilla game, you'll typically make back more than your original investment when you're reselling in the enchanted gear, assuming you can find enough merchants with enough funds to buy them all. As before, 75K is WAY more than enough to get this going.
Short answer, you've got plenty of money, don't worry that you'll waste it in some way.