10 billion before or after taxes ? If before, you will end up with 4.6 billion after.
Without going into the details of me, let me tell you I know a few dozen people that are in a position to own 11 homes in 11 cities, in fact some of them have owned 5-6 homes in 5-6 different cities - ALL of these folks have narrowed it down to just 2 homes - winter and summer.
Why ?
Because they spend more of their own personal time keeping up with the homes -or- travelling between them than they do actually living in them. Sure, they have 'keepers' to mow the lawns, etc., but that seemed to diminish the fun of having multiple homes. These folks have stayed where they are: the northern plains, and most of them have 'winter' homes - in Phoenix, Scottsdale, Tucson (2), Breckenridge, San Diego, Mobile, Orlando area, Austin, South Padre, and so on. Their kids, relatives and friends spend more time in these second homes than they do.
Cars.
I know of several people that have had 4-12 'super cars', and they ALL end up favoring ONE of them to drive 85% of the time, but usually drive a 'normal' BMW, Mercedes or Toyota as a daily driver, 2 of the guys have simple GMC and Ford pickup trucks. If you say you would drive them all equally, you'd be the first person on earth that ever did that. Knowing what I know about the Veyron, I'd never own one in a million years.
Also, some of these folks either own aircraft, lease aircraft, or have purchased fractional ownerships (NetJets), NONE of these folks do that anymore. If they need to go somewhere in a hurry (and the seldom do) they just call the airport and grab the next flight out, or they charter something.
I know 10 billion is fictitious - you can do all of the above and still have a ton left over, but I would find it more of a hassle - just like the folks mentioned above did. Just because they really did have 'money to burn', at some point you stop doing that, and your life becomes much less complicated.
If I had 10 billion, I guarantee you I would build and fund a couple of free children's hospitals such as St. Judes.
Quite honestly, I'd set aside 10-15 million for me to live on, and I would squander all the rest on worthy projects.