Nice discussion of this over on Slashdot today. This is a super-smart move on IBM's part. Their license promises some pain to companies who try to sue authors of any open source projects for patent infringement. Good move. I believe in the utility of commercial, Open Source (Apache, BSD, etc), and Free Software (GPL) - all useful licensing options for different purposes.
Of course the best thing would be to not allow software patents, but I think that is a lost cause.
I think that if market forces are allowed to naturally work (i.e., no corruption involved in passing laws that are good for the few and bad for the many) that in 20, 30, 100 (whatever) years, then we will see a progression to most software being either open source or small custom projects layered on open source.