I bought a macbook two years ago. I've used windows for years and was waiting for Vista, but heard all sorts of horrible stories about it, and then tried it and found it rather slow, despite 3Gb RAm and a dedicated video card, So I thought I would give OS X a whirl, and I could always dual boot windows on it.
1. The specs in my macbook were 2 GB RAM, 2.0 7200 Intel Core 2 processor and the usual stuff, you get cheaper PCs, but Macs always use something near the high end. No Celeron stuff or "duo" processors.The 7200 C2D processor in my mac, was the one with 4 MB cache memory, so a similar PC would not have been cheap. I've noticed, they always give you a mac with the latest processor (the move to Penryn was pretty quick for macs), you seem to get the latest tech, and the latest usually is more expensive and this was for the entry level macbook ( I added 1GB RAM)
2. There are a lot of extras you get, like the subtle, tiny webcam, magsafe charging point, LED lights to check the battery charge without booting, magnetic latch, sleek form factor, that you wouldn't get in most PCS, or none
3. I love the keyboard
4. Finally, the OS is just incredible, for instance XP always used to hang on me, crash a times, slow down after a years use, I would have to defrag, virus check, this and that.. my mac has never slowed down in over two years. Leopard came after a year or so, but I found Tiger so good, and didn't really want spaces, cover flow or Time machine,and stuck with Tiger. It is smooth, doesn't have that taskbar jitter on start up and works seamlessly with all my apps. It still works as fast, even though I have only 500 MB left on my hard drive, in some of my old windows machines, that alone used to slow the whole PC.
5. What I would like in my mac: Palm desktop for mac that is like the app for windows, a lot of software was a little better ( I felt) on the windows OS, which might not be so for mac, Nokia PC suite, things like that. No card reader for my macbook , wish there was one,
But all in all, I do 95% of my work on the mac, and only used the windows side (slow boot, slow work,and jittery) for syncing my palm and some programs, maybe games and I do not like MS word for the mac.. but text edit and pages serve my purposes pretty well too.
So, if you have a mac, and add windows, you have both, and trust me, you won't be using much of the windows. Unless Windows 7 does something radical, I feel macs will penetrate further into microsofts market share.