Would you own a doomsday bunker if you could afford it? What would you have inside it?
I've often considered what a bunker might look like, and just what kind of resources it would take to build and stock one. If you don't mind existing in a very small space it's probably not all that hard to do.
The big question is how long you'd need to stay in it. It's all very well eking out an existence for a year only to find the world is still radioactive and you finally ran out of food and die anyway. But on the other hand trying to maintain a stock of water enough to sustain two people for 18 months takes a significant amount of space, not to mention the challenges of keeping it clean. And then you need to get rid of sewage, keep warm/cool etc through an unknown event.
If money were absolutely no object you might as well live it up a bit. Run a bunch of solar panels, maybe tap into a nearby river to get some hydroelectric power, store up a bunch of batteries, a full-blown heating and cooling system, food, lots of books, and maybe a laptop/tablet so you can get some entertainment for as long as you have power.