I actually can't get my head around that kind of money. Surely you couldn't ever run out, with the interest it'd generate? It's like when people tell you how many people died in WW2, it's just too big to get your head round.
But, if I won a shit-ton of money, I'd get my mum and step-dad a nice cottage in the Cotswolds, my dad and step-mum a nice cottage in Cornwall or possibly a narrow boat, depending on what they'd prefer, give a decent but equal chunks to my brother and step-sisters, give something to Seamy to help him get out of debt, and then I'd have to wait a while but after my degree I'd buy a house in the Lake District miles from anyone but right near a lake - it'd have it's own jetty and everything - and get a little dinky sailboat and set up my little farm. I'd have three pigs, two sheep, six chickens, a rooster, two horses and a cow. I'd also get three dogs, four cats, two chinchillas and a tank of fish. Then I'd spend the rest of my life farming, sailing and writing. Oooh, and I'd bribe Steven Moffat to let me on the writing team of Doctor Who, but under the understanding that I could do all my work from home so I wouldn't have to go to Wales or Cardiff or wherever. Or they could come to me - I'd pay for their travel expenses, obviously xD And I'd hire a chef, and a gardener, and before the farm I'd go and travel for a year or so to see all the places I've always wanted to. And I'd go to the theatre a lot.