Once you get past the software buying issue (and bear in mind that Macs come with a bunch of bundled software, and also you get heavy educational discounts on Office, etc) there hasn't been any need for me to install boot camp. The Macbook is a good laptop, pretty solid although not to the Thinkpad T or X levels as said before. I have both the Macbook and the MacBook Pro (17"). However the polycarbonate Macbook is more prone to looking' used' than the TP's after a while. Build quality for Apples is about the same as Sony, I don't know if that's good or bad. There are heat issues (although of course if you Applecare it then you have peace of mind) and I think it would have perhaps been better to sacrifice some of the silence for better airflow. It's ironic that the silence which the Apples have results in people noticing noises they they wouldn't hear were it not for the whirr of fans on other laptops... therefore the 'moo', 'whine' etc that's been reported a lot. The 15" MBP is surprisingly portable, although it is a bit more 'precious' than the Macbook... although this might mean that you're more careful with it. As for aftercare, Applecare is the benchmark without question.
The problem with the Lenovos for me is that you really pay in bulk and a similar (and tankier) configuration is even more expensive than Apple. I used to have an X40 and although I appreciated it's solidity it annoyed me in the end because it was neither a super-usable full laptop (with the thing you plug in at the bottom) and somewhat compromised as a subnotebook.
The Sony's suited me more as Windows machines, and in terms of general design philosophy I like Sony/Apple's 'everything in one box, yet svelte' approach better. Problem with Sony is that the words 'Sony' and 'Support' are words which don't sit well with each other. I will have to say though that all my Sony's (and I've had various models almost continuously since the VAIO range came out) have been very reliable. It's just that
if they do go wrong...
I would say if you want to stick to Windows, despite the support thing I would recommend a Sony laptop with an extended warranty (perhaps even third-party warranty with loan machine guarantees, etc). The SZ series are slim, all-in-one laptops with 13.3" displays, dual-core processors and decent specs all around... basically like a Macbook Pro in the form factor of a Macbook.
But in terms of personal productivity, I'd recommend a Mac.
