Apple (NASDAQ: AAPL)'s newest Macintosh operating system -- Leopard -- will officially go on sale October 26 (just under two weeks from today). Unlike Microsoft (NASDAQ: MSFT), Apple releases new operating systems every year to two years. By contrast, the time difference between the release of Microsoft's Windows XP and Windows Vista operating systems was over five years.

That being said, so Mac users flock to upgrade every time a new operating system comes out? Hard to say, but every Apple fan I know borders on zealot (this is not a bad thing), and they do indeed upgrade every time something new comes out. I sense in many cases this is nothing more than psychological pride over genuine utility addition, but I could be mistaken.

Will Leopard's release bode well for Apple's coffers, then? Sure, but the question of how much is still up for debate. Apple's iPod phenomenon -- and now, iPhone phenomenon -- has translated into a growing market share for Apple PCs, and this "halo effect" has been tracked and followed with journalistic vigor in every nook and cranny of the media and blogosphere. What more could yet another upgrade add to this honey pot?

Apple's shares are sitting at an all-time high at the moment due to the perfectly-timed release of new iPods in September, along with the growing market for the revolutionary (yet already outdated in many ways) iPhone. Adding new eye candy to Apple's PC market will do nothing but help bump the company's stock price to over $200 if holiday sell-through does well. Perhaps the iPod was just a means to get customers flocking to Apple's PC segment, since in the long term, the iPod's remarkable sales sustainability can't keep up the torrid pace it has in the past -- or can it? Regardless, the company wants customers buying new PCs to think "Mac" instead of "Windows," and a newer version that looks and feels better than the last will only help that effort.