Below is a screenshot of a very large infographic showing the history of Microsoft (and Windows associated products) and Apple (and Mac/iOS associated products) from 1984 until 2011. Click the source link for the full size version.
I'm pretty sure 10/24/1985 wasn't a great idea at post-Jobsie Apple, it took until 3/1/1988 for them to realize this.
9/14/2000 however, was a bit of a set back for Gatesy.
10/23/2001, whoops, Apple back in front.
10/22/2009, Sorry Apple, Win7 > OSX (I un-converted).
I do think it was interesting that they left out June 2006, when Apple hardware just became prettier (and much more expensive) PC hardware...
|Image source (and full size version) -> http://www.manolution.com/wp-content/uploads/2011/06/history-of-computing-full.png|
Source -> http://www.manolution.com/2011/06/microsoft-vs-apple-the-history-of-computing-infographic/#more-173
More charts! -> http://www.dannyfinnegan.com/2011/01/i-love-charts.html