Nobody would know I was filthy stinkng rich. I'd act the same, dress the same, and be the same. I'd make sure my kids were set up for college and a little to get them started off after that and then I would use the rest to take down the Japanese whaling fleet, end the dolphin slaughter in Taiji, and take on the cetacean murderers throughout the world and bring an end to their barbarism. I'd stop the finning of sharks as well.
Money is bullshit and the root of all evil, so I would make sure it was used to battle the evils in this world.
I would probably also do a lot of work with children's groups.
My one personal splurge would be season tickets to the Red Sox, Bruins, Patriots, and Celtics. Since I couldn't go to all the games with my busy schedule, the unused tickets would go to children's charities in the Boston area.
I would, of course, live in Boston...likely on Commonwealth Avenue near the Back Bay.
I would convert my car to run on a completely renewable source. My home would be 100% off the grid and supplying my neighbors with free energy.