For me, it would be a huge music studio, with all the latest gear & instruments. I've only got so many years left, and I'd like to get this scratched off my bucket list. Of course, there'd always be diapers, as there have always been. Money does change things. I had a nice studio already (had to sell the house, and my fave electric, boo hoo), but the music energy keeps coming...
OK, so what would I really do? I'd have yearly get togethers with all my family members, cousins, aunts/uncles, brothers' sisters, nieces & nephews, at a remote location, all paid for, and all of their weekly salaries paid for, as well. I'd hope for everyone to just relax for a couple weeks, and to just enjoy each other, a nice ocean, a nice beach, a nice villa, SOMEWHERE. Food, drink, conversation...
What I would avoid would be granting money to anyone specific, without a similar grant to others in the family. With that, I might have a threshold limit, maybe $10,000-$25,000, or whatever, but, ONCE REACHED, never again. Nobody learns anything from a handout. If someone was seriously sick, AND, only my money (albeit, some portion of it...), not insurance, and not the government, could bail them out, then, that'd be a situation to consider on a case by case basis. I've had family members that hit the IL lotto already, and a friend, as well. The friend lost his brother the next year. Money did nothing to help. My family members were both dead in a couple of years, leaving my cousins to fight over what little was left. They're my first cousins, and I've never had an adult conversation with any of them...