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Switched to Mac in 2004 because I wanted a small but powerful laptop for uni work, so I went with a 12" PowerBook.
Now I buy them because it's cheaper than buying a powerful PC and powerful Mac, as I need software on both systems, so I buy a high-end iMac every so often.

I'm not opposed to switching back fully to Windows. If Apple does go the way of "iOS on desktop" then I'll be back on Windows in a heartbeat. I just like Apple hardware and their build quality.

You may want to look at Windows 8 before you say that....

We actually as of yesterday were told to halt any work on in house apps compatibility with Windows 8. Its so bad our company who constantly upgrades everything for whatever reason will not be upgrading to 8 (and we upgraded to Vista before!).
 
I was running Windows and used to love it...then a friend of mine online showed me Ubuntu four years ago. I downloaded it and eventually used it to replace windows. Unfortunately the amount of trouble I had with it wasn't worth it, and after being locked out of the system three times and losing all data, I decided I wanted a Mac. I certainly didn't want to go back to Windows, and after hearing how everything on a Mac just works like it should, I got one. I've been using the same MacBook pro - 17" Mid-2009 model and it still runs like the day I got it, in mint condition at that.
 
Bought a 17" G5 iMac for my wife on Christmas 2004 because she was eyeing one and I heard that it would be easier for me to maintain (and it was!). The next year I bought an iBook for travel. I didn't make the full switch for myself until the Intel models came out, with an iMac in November 2006.

The 17" G5 was given away and is still in use.
 
You may want to look at Windows 8 before you say that....

We actually as of yesterday were told to halt any work on in house apps compatibility with Windows 8. Its so bad our company who constantly upgrades everything for whatever reason will not be upgrading to 8 (and we upgraded to Vista before!).

The lovely thing about Windows is how well supported it is. Windows XP had a decade of support, so if Windows turns sour at least I can stick with Windows 7 for a while yet.

Besides Microsoft are great at listening to what consumers want and the whole point of a public beta, a lot of my colleagues had emails from Microsoft asking for indepth reviews of the system. It'd be nice if Apple extended the same courtesy.
 
I got my first Mac as a present and subsequently bought more after because I think they're good computers. I plan to upgrade to another new Mac very soon, though I may dual-boot OS X and Linux :)
 
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