A perspective from outside the Mac camp:
I just spent three weeks on a software contracting project making Mac software. The experience (as software developer) is sort of like driving on the left side of the road - you can learn and get somewhat used to it, but it never feels quite right (call me an old dog - in Australia I accidentally went around a roundabout the wrong way). I'd say the development experience on OS X is quirky. Of course, as an end user it's the software that matters more than the OS so as end user your experience might be more positive.
I did some software testing running Windows XP on Parallels on a prev-gen Mac Pro dual quad a month ago, performance (for image processing) was unimpressive compared to running XP in a VM on 64-bit Vista on my two year old Thinkpad. The guy who set up the Mac is an expert user, we could not find anything wrong with the setup. I've never used Fusion - perhaps it's better. As for people saying VM on a Mac is fast, they are probably comparing to an older PC (right Jack?).
One guy at the office where I contract has a new Macbook alu, it looks great and the screen is nice and clear. He wouldn't let me profile it though - it's strictly hands off hehe. I'll work on it, see if I can get a chance to run i1Match on it. Beautifully made hardware, and the display has quite wide viewing angles, I don't think it's a TN but it's not as good as the IPS on the T60 Thinkpad... that thing is really glossy though, I didn't think it would be so bad, it has dual reflections one from the screen and one from the cover glass. Even my five year old glossy Sony A190 has great AR coating - Apple needs to get with the program here. Jack would you agree since you had the same Sony (or was it A690)?
I'd say take a close look at the 17" Macbook Pro, the specs are really impressive. More pixels, huge battery, not too heavy, optional matte screen which is a must until Apple fixes the reflection issue, supposedly wide gamut panel (according to Apple it's significantly better than the 15" panel).