I know I'm not free of human failings, so I would spend much of it on a number of things I've always wanted to do or buy. However, I'm also generous enough to give much of it to charities that need it desperately.
On the subject of large amounts of money, I think all of us wish at times to win the lottery, but if the U.S. bank crisis has taught us anything, it is that for many people, even staggering amounts of money are not enough.
One other sobering fact - the rate of suicide and divorce for people that have won the lottery is significantly higher than the rest of the population. If money could actually buy happiness, this would certainly not be the case.