Their war chest will remain strategically as big as it needs to be. The amount of cash they have is ridiculous.
And while an Icahn sized stock buy back is probably too much, their current buy back makes all the sense in the world. The stock is tremendously undervalued.
You can't say it more eloquently than Warren Buffet: "If you could buy dollar bills for 80 cents, it's a very good thing to do." [1]
[Disclosure: I am long AAPL.]
1: http://tech.fortune.cnn.com/2013/03/04/apple-warren-buffett-...