A really good sewing machine. Fabric. A catio for my cats. Books and CDs. Amazon Prime. A season pass for The Good Wife on Amazon video. Kitchen remodel (I waited to do this for 27 years, spent a ton of money on it and love love love it every single day.) Baseball tickets for the whole family.
Simply Orange brand of orange juice.
**Charmin Ultrasoft ** from Sam’s Club.
I am super cheap. My idea of a worthwhile splurge is getting the real Oreos instead of the fake ones. Sure, they cost $1 or so more, but nothing tastes like an Oreo. So a few times a year I spend that extra buck.
Feeling a little guilty about that $6.95 monthly box of haircolor. I held out a long time, but it is worth it to cover the gray. I still cut my own hair, though.
For the kids: music lessons, college
I guess the biggest splurge I’ve made in recent years was a custom-built titanium bike, with S&S couplers, that was built to fit me exactly after a two-hour bike fit. It felt absolutely obscenely expensive at the time, but I love riding it and have gone from thinking a ten-mile ride is an exercise in self-abuse to enjoying a forty-mile ride. Since DH thinks cycling is the best thing ever, this means we now go for bike rides together. So absolutely a huge payoff in fun per dollar.
Just mix a half portion. That’s enough to touch up roots.
Good cookware….saute pans and le creuset , if you really like to cook. Any fine pieces that are meant to last a lifetime…good knives.
Also, good pet food. My dogs eat a brand that I have to buy in a specialty shop , but they never have stomach / digestive issues and their coats are nice, they don’t smell bad or doggy
My dog’s chiropractor.
Breakfast in the garden or back room of the Soho branch of Laduree’. Really, you would never imagine that something as simple as eggs, coffee or breakfast pastry could taste that good.
http://sweets.seriouseats.com/images/2014/02/2014221LadureeBackRoom.jpg
@nottelling I don’t splurge on clothes, shoes or handbags either. Which means I always feel slightly underdressed at the fancy restaurants (we generally only go two or three times a year.)
One thing we splurged on a couple of years ago which was totally worth it was having an individualized tour of Jordan. We told the company what we wanted to see, which included going to pick up my son from his semester abroad one of the days. It saved us so much time and our driver was a lot of fun.
Things I will never splurge on: cars and fancy wine. My monthly transit pass is worth every cent I pay for it though, and Eroica is a fine Riesling, BTW.
Metropolitan Opera season tickets
A wedding planner
A good haircut.
Pajamas. (Yes, that’s right - pajamas. They’re not all the same!)
Real maple syrup.
Fresh squeezed orange juice.
eta: Oh - and a Mac instead of a PC. (I will never go back unless forced to…)
A seasonless pantsuit. A pair of shoes in the $200-$400 range. I can’t have enough Kate Spade bags.
Date night at a place that serves food slowly.
Gonna pose this question. My opinion, may not be yours.
To me a splurge is an exception in what you can really afford but one area you choose to spend anyway.
So to me, if you can list half a dozen regular splurges, it isn’t really a splurge, it just so happens that you have the $$ to indulge. Is there a difference? There is to me.
abasket – I agree with your definition. I just splurge more often than my budget allows so it looks “regular” when it really should be “rare.” 
I used the guidance in the OP in defining "splurge - something you can live without but’s it nice to have, so you will spend additional for it.
A Tesla! We’ve had ours for about a year and love it. Doesn’t hurt that DH can charge it at his office. That also means that I don’t get to drive it too much, but he’s out of town for a few days so I’m going to play with the new(ish) autopilot option.