I would take a sports almanac so that I could parlay a small amount of money into a lot. I would then buy in as a major shareholder in MS. I would let Commodor crumble just as it did. (Sorry guys, it was going to happen). I would then come back to the future, sell a few dozen million in stock, and buy the all rights to the Amiga from everyone that has touched the name so that all IP is unified back under one company. Following that I would hunt up the major developers of current Minimig and Aros stuff, and give them a nice 6 figure salary each to make me toys.
Don't worry, I would let you guys play with them too.