I now use a Mac. 

WOW.  After being a "Microsoft" programmer and a project manager for a good chunk of my career, I have now switched to Mac full time. 

If Microsoft can't keep me as a customer, they are in trouble. 
Why did they lose me?  Simple. 
I want my computer to work – all the time. 
I don't like it crashing.
I don't like it going slow.
I don't like having to learn how to fix problems in the registry.

7 month agos I bought a brand new HP Laptop with Windows Vista and Dual Core Intel / 4Gb of RAM.  After a few weeks, I realized it was pretty slow and clunky.  I'd even been using Vista since it came out so those issues were nothing new for me. 

Fast forward a couple months and my HP laptop keeps getting slower and was getting more and more buggy (even with the what seemed like millions of windows updates every week).  Every once in a while it would just crash.  Every time I closed powerpoint I would get an error.  Etc. Etc.  I'd had enough and wanted to find something better.   

So, I bought a used Mac on EBay, just to confirm that it would work for my needs.  It did and after about a month I bought a brand new MacBook Pro.  I was then able to install Parallels, install Windows on my Mac (for a few apps, namely Quickbooks) and have both on it  Guess what?  After a month, I only use the Windows side on Parallels for accounting or testing websites on internet explorer. 

I am a full convert, and unfortunately for Microsoft I'm not alone. 

My wife had never used a Mac and she isn't nearly as technically educated as I am, yet I gave her my old mac laptop with no training.  Two days later I came home and she had printed about 20 pictures using iPhoto and our wireless printer.  It's been a month and she loves it and guess what?  It's never crashed, nor had any problems.  Another convert.

I'm the last person who would have expected to switch, but I did and I couldn't be happier.  Macs used to have 3% of the OS market, now they are around 7%.  Why?  Because they work. Simple. 

What's the lesson here?  I see two of them:
1. Develop a superior product, market it well (as opposed to IBM's O/S 2) and even with a company that seems to have a huge monopoly over you, you can gain market share.
2. Rest on your laurels, release products that upset consumers, and watch your market share fail.