I've been a Mac user since 1990. I saw SimCity in a store, and was captivated by the colors, the menu system, and the iconography. I demanded that the next family computer be a Macintosh LC. I bought a Mac Classic with my own money on which to run a BBS. In the late 90's I installed MkLinux on a Powertower 180. Gaming without a discrete graphics card, BBS server on an all-in-one, and Linux on a closed platform; for a very long time I have been using the right platform for the wrong reasons. Ironically, the advent of Steam for Mac finally inspired me to build a gaming PC.
My current computer is an iMac from 2007. It has a huge, beautiful 24" screen that looks just as good as the day it arrived. I originally bought it to placate my World of Warcraft gaming, but soon after gave up the game. Since then it's been a fantastic machine for all that other stuff that you use computers for, like spreadsheets and Flash games. And when Steam came out, I thought I'd finally get to play some real games on it. I downloaded Portal (which I had played years earlier on Xbox, don't worry), booted it up... and found out that my video card was too old. What do iMac owners do when faced with such a problem? They have to buy brand new computers.
That's just wrong, right? I want a gaming computer, but one that I can plug into my TV and use from the couch. After looking at new Mac prices, considering the underpowered 2010 Mini, and doing some research, I found that I can build a machine that will play everything I wanted to play on the PC right now for $800, while a comparable Mac would cost twice as much or require me to sit at a desk. Apple just isn't interested in making a gaming computer for me.
What Steam for Mac really did was make me realize how much I was missing by not being able to play PC games, and by offering me some of that, it made me want the whole thing. So come this fall, probably with the release of Cataclysm (which I just want to check out, just a little, I promise), I will be building a gaming PC.