Houses and/or condos all over the world and the time and money to spend going from one to the other, on my own schedule. Several private airplanes would be nice.
And many more years than I have left to enjoy them with my Darling Marcie.
good wine
great art
if money is really no object, there are a wide variety of boats I would enjoy. Small sailboats, canoes, big sailboats, fast ski boats, a yacht or two.
Horses.
Lots and lots of horses.
Oh… and dogs, too.
Well, my library, pantry, and zoo would be top-notch. I’d also have an impressive video game, anime, and art collection. Then there’s the harem 
DVDs. I only have about a third of the collection I’d really like to have.
Geeky figurines from Gentle Giant et al.
And though it’s a hobby I’ve long since abandoned, model railway setups.
Wine. I don’t even like wine all that much, but I do like the idea of having a huge, superbly stocked wine cellar.
If money and space **and **the opinions of others were no object, I’d have lots and lots of women. Much like Hefner and the Playboy Mansion, except these would be more explicitly prostitutes, and I’d pay so well that I could attract girls who are cute *and *smart.
Books, hell.
I would collect libraries.
I thought those were a given.
Books.
Fossils. Dinosaur in the foyer!
Maps.
Islamic calligraphy.
Oh, and a kennel full of (healthy, not dangerously inbred for size/overweight) dogs the size of horses. Who would all, of course, think that they were lapdogs. “I’m just a little puppy! Yeah, when I lie on your lap only my shoulders can fit, but I’m still a lapdog!”
One of my goals when I become an Evil Overlord is to breed giant chihuahuas! I figure that a bunch of really high strung, giant dogs will make things “interesting” for folks.
Really great, top-of-the-(kite)line, state-of-the-art kitemaking equipment and supplies, (including rolls and rolls of ripstop nylon in every colour available)
An ultralight helicopter (the Vortech types) [They’d fit inside]
Many Cats (I’d give them all a good, loving home with me)
Books
Some extra bedrooms (in case family or friends found themselves without a place to stay)
Lots of secret passageways and secret rooms (I’ve always thought that would be pretty neat!!!) These would be separate and distinct from the extra bedrooms.
And probably some other stuff that I can’t think of right now!
Dogs. I only have one dog and I want another, but I like big dogs and they eat big food and take big pills and have big vet bills.
Plus, I’ve only got the one dog and we can barely fit together on the double bed. So I’d need to get a nice place for me and all of my dogs to sleep.
If I had a whole barn full of tools, tho - well, I’d build somewhere for us to sleep 
:smack: How’d I forget the cheese?!?
At first I was surprised that there were so many “BOOKS!!!” answers, but then I remembered where I was, and who most dopers are…and I smiled…
For me:
Books- I’m not original, but whenever I do get my own house I want to have some type of Library/Big-ass bookshelf
Dogs- I love dogs SO much. Mostly Great Danes, but some smaller/medium size dogs too (corgis!!)
Games- All sorts. Board, card, video, pool, air hockey, ping-pong, foozeball, darts, pinball…you name it, I love games.
Jerseys- It’s always been a dream of mine to own one of every NFL team’s jerseys.
There’s more…but I can’t think of em now, and I prolly will once I click off this page.
motorcycles, mountainbikes and guitars all immediately come to mind, especially within the ‘I really don’t need another one’ framework.
Having read this thread though, I’d like to add lots of cute panties, appropriately occupied
Too late, cats’ got it
Legos.
Books.
Cartoons.
Cats.
Pictures.
Sculptures.
Tools.
Music.
Computers.
Every dream house I design, the workroom and studio space end up bigger than the bedrooms and the kitchen combined. And I’ve wanted a Room Just For Legos since I was old enough to discover Legos for the first time (3).
Is this your desk?
Lunar real estate.