My current Mac (bought in February) is my first. Prior to that I used an ancient toaster Mac at university circa 1987 to do an assignment that required Hypercard, prior to that I'd never touched a Mac at all. The cost, the OS and the fanatical zealotry of certain parts of the userbase more than countered the droolworthy Mac-only apps, and eventually the Mac only apps became available on the PC, Windows became vaguely usable and so forth.
I only really got interested when my wife (who also has no prior Mac history) started gazing longingly at Titanium Powerbooks whenever we were in CompUSA and dropping broad hints. So in January this year I bought her a 667MHz TiBook, primarily for Bonus Husband Points - I wasn't particularly interested in it myself. Like I said earlier, I had no great fondness for MacOS.
However, I was present at the opening of the PowerBook box, and was impressed by the presentation. My wife skipped most of the setup and immediately changed the startup disk to boot OS X. I was then impressed by the OS X setup procedure, in particular the ease with which it could be hooked up to my existing WiFi network.
Then I was impressed by the OS X desktop and the familiarity of everything "under the hood". Then I started poking around the info on Apple's site about the developer tools, reading about the Cocoa frameworks and Objective-C (which previously had been thought of as "that thing that's supported by gcc that nobody actually uses").
The final straw was that over the period November-January I'd gone through no fewer than four different motherboards on my XP PC trying to find one that was stable, had wasted entire weekends lapping huge heatsinks to try to get the Athlon in the box cooled adequately, and still wasn't that much further forward. Oh, and the continual desire to upgrade the machine was a money pit.
So, succumbing to what I've termed "homebuilt PC upgrade cycle fatigue" I decided that what I wanted was a machine that would work right out the box, that wouldn't require me to pour the sort of money into development tools as was required on the Windows box (where I'd just ordered Visual Studio .NET), and that would last a lot longer before it began to feel obsolete.
The end result was that in early February, I talked myself into buying a dual 1GHz PowerMac. I've been very happy with it, even though it's turned out to be a money pit of a different sort (Apple Studio Display, Adobe Web Collection, GeForce 4 Ti upgrade so I can hook the Studio Display and the Samsung Syncmaster LCD that used to be on the PC up at the same time...)
The PCs still there, the idea was that my wife and I would both use it for the few remaining things we *needed* the PC for (PCAnywhere in her case, .NET development in mine). However, the machine is lucky if it's switched on once every couple of weeks, and even then it's usually only to download and install the latest Critical Patches.