I'm completely in agreement with what Dave has said. Many people do a technical comparison between a Mac and a similarly specified PC and decide that the Mac is expensive. What they are not factoring in is the intangible -- the experience you have with the machine, not just in using it, but throughout its lifecycle with the Apple Store (my experiences of service and the way they treat their customers have all been really good). It's not just a question of looking good -- it's also the fact that everything is put together with care and
love, meticulous attention to detail and the seamless integration, from the veneer of the user interface, to the technical aspects that you don't have to think about at all, and everything in between.
And then there's the
community. I have virtually 'met' (as well as physically met) many great people who are fellow Mac users as well as listened to, and participated in some great Mac podcasts. Many of the people who buy Macs do so because they love them, which means you find other people passionate about the products, even if they weren't really 'computer people' before. My experience of the Mac community over the four and a half years I have been a part of it is that it is vibrant, helpful and friendly.
If you're a Linux geek, or Linux geek in training, Mac OS X is fantastic because it gives you a strong graphical operating system
and almost everything you'd come to expect from a Linux command line world too. (It's actually closer to BSD, so there will be slight differences, but a large number of skills are transferrable). For me, the Mac is my primary system exactly because it saves me from many a headache with things that otherwise need fiddling and configuring, but when I
want to get geeky, it's all there.
There are disadvantages too, and you should be aware of them. The Mac is, primarily, a 'closed' hardware platform. The benefits of this are that everything often works beautifully, but it means you do have less control and flexibility over your own stuff. You will be much more dependent on Apple and authorised resellers to fix your Mac if it goes wrong, which can be expensive out of the warranty period. Upgrading things yourself is more difficult, and you take more risks in doing so. Sometimes it's a right pain -- try swapping out
a hard drive in a recent iMac (you have to take the whole screen off!).
The software is also heading in the direction of becoming more closed too. With Mac OS X Lion, it is moving into a direction where, like the iPhone and iPad, Apple have control over software. Right now, you're still completely free to do what you want in terms of installing stuff on your Mac, but in the future, I suspect new applications may only get new operating system features by going through Apple's Mac App Store -- and in doing so, agreeing to Apple's rules. This is just me speculating -- but it's an issue that must be remembered for the future of the Mac platform.
Be aware as well of what data you're putting into a proprietary format. I think you should always be reasonably well prepared to jump ship back to a different platform if you suddenly need to. I export Apple Pages documents, for example, so I can use my data elsewhere should I need to (even if that means that some of the fancy features won't be available to me if I did).
I bought a Mac in early 2007, and I've been very very happy with joining that community. I haven't given up Linux, or indeed given up on Linux. It has changed the way I use computers, and changed my primary OS, but I have always had an interest in keeping up-to-date with
everything, so my love of Linux has stayed. An investment for the Mac doesn't have to mean a loss for the Linux world. :)
Ultimately, weigh it up, think carefully and make an informed decision. I did exactly that some years ago and I have not regretted it.