Considering a Mac
I've preferred Windows machines over Macs basically since my first chance to play with Microsoft Windows 3.0. A decade ago it was easy for me to say that because of ideas like multitasking--Windows couldn't do it very well, but the Mac was just downright poor. Apple has made a lot of changes with it's OS X platform, however, and it's always been something I've kept my eye on.
Over the last several years Apple has been releasing some great stuff--I use the iPod and iTunes every day. For the last two years at my day job I've been using a 20" iMac running Tiger. I mostly like it; I guess my chief complaints are mostly simple fixes with other software (Quicksilver looks great) but installing applications is greatly frowned upon. The Dock is a much nicer tool than the Windows taskbar is for keeping things at your fingertips and still being manageable. As far as my day-to-day experience, that's about all I can say.
Looking ahead to how I would like to use it, though, I see a few advantages that become more clear all the time. Primarily, in relation to web development, having a local unix-like system to test my latest plugin on--similar to a typical real-world web server--along with a nice graphic interface, and clear support and documentation, would be a real advantage. Similarly, being able to run Windows alongside (via Boot Camp or Parallels) could also be a substantial advantage.
Apple's soon-to-be-released Leopard is really the thing that fuels the desire further: Time Machine seems like just the sort of simple backup/versioning tools I've wanted; Spotlight has some great refinement--in addition to search it's a calculator, dictionary, and links to Wikipedia; Stacks would be a great way to semi-organize the day's project; there's a system-wide grammar checker that I haven't seen touted much, but sounds useful.
So what Mac would I get? The 24" iMac would be a good fit, especially since it looks like it could also extend my desktop onto my other 24" screen! Portability and other future needs makes me look at a MacBook Pro, however. I do find the prices a little hard to swallow, though, given that I've always purchased low- to mid-end computers. I'm not saying I think they're overpriced--I don't--just that they're expensive.