I did receive a windfall of about that size (my mum died before my grandmother, so my brother and I split her share of my grandparents' estate). It is all invested - I hope to be able to pass a significant portion onto my nieces and nephews. It did allow me to make some risky career choices (ones that put me into the position of of great future benefits, but involved considerable short-term risk) and gives me "screw you" money (so I don't have to take/keep a job that I don't want). It also gives me the feeling of having insurance in case anyone in the family needs medical care that isn't otherwise covered (my mum needed a lot of expensive medical care - luckily it was covered between provincial health care/private insurance, but it definitely taints my thoughts).
Honestly, I'm probably one of the few people whose father's tell them to spend more money (when I was worried about taking the career risk, for example, my father pointed out that I was worrying unreasonably). I'm not a miser (I swear), but I do probably err on the side of worrying to much about having plenty of money for the future (and leaving money for the next generation).
