I bought a powerbook as my first mac around 3 years ago, and recently bought a new imac (one of the 'infamous' ones with all the freezing problems, and the dodgy 24" screen - actually the screen is great, and I have no freezing issues after several months of hard use). I've loved them both so far, and wouldn't go back to windows.
That said, macs aren't perfect and are definitely way behind windows in lots of areas despite what many on these boards will claim, and apple's limited range of computers can be very annoying (e.g. the laptops - choice of expensive but very nice high end laptop with a big screen, or a cheap low end one that would be near useless for gaming etc. and with a very small screen).
I'd say macs tend to be very well built and designed compared to other PCs, and the specs tend to be pretty good. They're actually not expensive really on the whole too. The OS is reasonably secure and stable (I'd say it's actually similar to a windows box that's been well configured), but OSX doesn't seem to get slower and buggier over time whereas windows needs a full reinstall every 12 months or so I find.
In use, I've found that I've been able to do everything I wanted to on the mac, in general much easier than on PC. Once you find your way around OSX it's much easier to use than windows, and much nicer. You're not constantly harrassed by pop-up messages reminding you that new updates are needed for 3 different bits of software, you don't really need to run a virus checker (at least for now - that could change as macs are getting more popular), and you don't need to worry about spyware and the rest of it as long as you're sensible.
The main thing though is that they're pretty dependable. I've actually got most of my family moved over from PC to mac in the last couple of years (I provide support them, and got sick of panicking after hearing that the PC had mysteriously slowed down and started popping up adverts when they weren't on the web, but they could still do their online banking!) and have gone from fixing or updating something every couple of weeks to hearing almost no complaints. Same for me - I've had a few issues with both macs, but nothing major, and nothing compared to what I've had with any of my many PCs.
Overall... I'd say that feeling you get with a brand new freshly-installed pc, where everything works and feels really fast, is what you'll have with a mac after a year or two. You'll keep finding lots of nice little touches that make life easier, and you'll be free from the drudgery of keeping everything updated, secure and working that you get with a pc. You shouldn't have any regrets, if you do you either chose the wrong model or got unlucky and received a faulty one (in which case send it back, don't just hang around on sites like this complaining about it
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