I would fill out my Morgan collection, then the WLHs, followed by Peace dollars. I really want a good 2 cent piece. I was offered one once, but chickened out. After all that, take care of family and friends.
I would put together a great, illustruous collection of Magna Graecia coins. But then, after a few months, you'd all probably accuse me of being a new, even worse, version of Cl......o, and nobody here on CT would want to talk to me anymore. I'd miss that. Man, life's hard for us billionaires...
I would get one each of all of the worlds trade dollars, in the best condition possible. As for a car, I would replace the 1967 Pontiac GTO that I sold, foolishly, in 1973, and I would replace the 1969 Jaguar E Type Drop Top and/or the 1971 Jaguar E Type 2+2 Hard Top, that I failed to pull the trigger on in 1974. I couldn't make up my mind and by the time I did, I had already quit my job with Galveston County Engineering Department, whose Credit Union was willing to finance anything I wanted, so long as I continued working for the County. I quit the job because of a co-worker I thought I was in love with. I just wanted to get away from her. Thinking of her...um...personality... was driving me crazy. In my impetuous youth I made many foolish decisions that I later regretted. First the Trade Dollars, then I'd look around.
I would have a comparably sized collection to today, certainly not exceeding 200 coins. The challenge is finding the coins for sale: even with endless funds, it would take probably 10-20 years to track down the various types I would want.
I might just bid on the most expensive coin coming up next for auction. I'd probably try to get my hands on some mules. Buy some of the most expensive genuine vintage coin rolls I could find...and search them! Then I'd have my assistant post on cointalk announcing a budget for everyone! And do my version of Oprah ...You get a coin, YOU get a coin...EVERYONE gets a coin!!!
Plenty of superb Roman aurei, a colosseum sestertius, an eid mar denarius and a few late Roman medallions. I've always loved the large multiple siliquae/solidi denominations because of their exceptional artistry.
One of every Augustus Aureii, silver tetradrachms, denarii, As and Dupondi and any other bronze coins ever minted in his name, including the posthumous ones
First thing I'd do is see if you want to sell your collection Joe? Failing that, I would next search for the Hunt/Kunstfreund Athens dekadrachm. I have an old "Australian Coin Review" from 1980 that my mum bought me when I was a kid. Big story of Nelson Bunker Hunt paying a world record price for it. The picture of that coin is what ingrained my interest in ancient Greek coins. Anyone know where that particular coin ended up by the way?
I see that most, if not all, the replies here are supposing the lottery prize is only one million dollars. The fact it's one billion dollars. In this respect, I'll be searching for gold statues of Hadrian, Augustus, Faustina II, Constantine, Julius Caesar and Cleopatra VII. I would also buy all silver dollars that are DMPL, no matter if they were MS 65 or MS 61 or AU. There are also ancient beautiful vases dating back over several centuries BC. They are in nearly perfect condition and figure the lotus flower, Phoenix, famous historical events and mythological scenes, beside love stories.. I think now I have to stop dreaming.