Obviously a split makes the shares more affordable for more people. More people can afford to buy an $80 per share stock than can a $1600 plus per share stock. Microsoft is, even at $102 per share, extremely cheap by comparison. I'm curious to see where the Microsoft stock goes, especially since it's gone through 9 splits in its history. It would be great to see it rise to Amazonian heights. I guess time will tell.
There's something psychologically prohibitive about buying a stock in the thousands of dollars. If you have $5,000 you can only buy three shares and that looks pretty lowly in your accounts. $80 bucks per share after the split really is more affordable for the smaller investor, and the smaller price probably would encourage more investors to get aboard.