We often discuss this (I buy a lottery ticket every few weeks). My first concern would be my husband's African family (six brothers and sisters and their assorted children). We'd like to rehouse them all in a better district. Then I'd like to contribute to various charities such as Water Aid and UNICEF etc. My lovely neighbour who runs an animal sanctuary with her gay partner would also receive a goodly sum to help pay for the winter fodder and vet's bills etc.
In my husband's ancestral village Nafamadougou in the north of Ivory Coast the inhabitants would greatly benefit from a tractor to help with the cultivation of their food.
I'm totally uninterested in buying designer stuff (Gucci handbags, Rolex watches, diamond jewellery etc). And it would break my heart to leave this bungalow in our little Norfolk village.
Actually, I reckon winning a huge sum of money would create much stress and worry. Big Lottery winners have been known to ruin their lives with the ensuing problems.