The Lotto in my state was estimated at 2,000,000 last night. If it was at least four times as much, my answer would be completely different.
I'd start by putting a building out back to house a listening room and some storage.
I'd have some of the gear I already own completely redone (a few amps, a couple of tuners, one preamp, a couple of cassette decks).
Once the listening room was finished I'd cycle through all my speaker and amp combinations and narrow it down to a primary and maybe two backups.
Then I'd do the same with sources. I'd probably end up getting a new fancy schmancy turntable, a new dac and a really nice, perfect condition old reel to reel deck.
I figure all of the above would cost ~$125,000. I'd expect that (especially the purpose built listening room) would yield better results than just plunking down the same amount for all new gear.