I bought a Mac after 13 years of Linux. I have adjusted and still run Linux in parallels, but rarely use it. Really, the question of switching is not one that should be considered merely in the context of PS, but rather as an environment. It will cost more. It will have less bugs / viruses. It will possibly have different software availability / updates / versions. The one guarantee is that because of the consistent hardware environment, things will 'just work' more often than not and more often than under windows.
I think that Nando's advice is right-on: don't buy it to make it into something else.
Hey, another Linux guy!
I've been a Mac user for about four years. Before that, I had a Linux desktop for three. Before that, Windows. My day job is supporting an office of 200 Windows workstations. I use a Mac at home because I don't want to spend more than 8 hours a day dealing with Windows problems. That's originally why I ran Linux, and it did the job well, OS X is just a more refined UNIX.
Servers, on the other hand, those are still Linux servers and probably will be for a while, I particularly care for OS X as a server.
Go to an Apple store on a weekday when there aren't tons of kids checking their facebook and try it out. Open up Aperture while you're there, too. If you find yourself liking it after an hour, you can buy a refurb from Apple's website (usually at 15% off) that will have the same warranty and will be the same quality product you'd get if you paid full price. If you don't like it after a month, you can sell it on eBay for what you paid for it. Don't buy AppleCare when you buy it, you can buy it up until the last day of the one year warranty. Save your money and think about it for a year. If you do buy it, buy it from a reseller on Amazon, you'll pay two thirds the price you would in the Apple store. Yes, this is legit.
On the other hand, if you go to the Apple store and don't like it and keep wondering how you can make some task more Windows like, don't buy it. There are some people who just cannot accept that OS X is different and they will spend the entire afternoon cursing it for not operating exactly like Windows. (Maximize button anyone?) It's a different way of approaching a task and if you cannot switch, don't bother.
Use either VMware Fusion or Parallels to run your Windows only applications, Bootcamp is annoying, who wants to keep rebooting?