If it's a choice between Apple and Dell, I'd probably suggest Apple (doesn't sound like you're a gamer, and anyway there are recently loads more 'windows' games also available on the Mac).
BUT - that's just because I'm horribly biased against Dell. If it were a different PC manufacturer, I'd say get the win7 laptop :)
I have used Mac Pros and Macbook Pros (I'm currently writing this on my work Macbook Pro), and build my own windows machines for home. In my experience, windows 7 has been more stable than MacOSX, and I find windows 7 also boots and runs faster than MacOSX.
I like Apple's design (more than any other laptop manufacturer I've seen so far), I like that it's built on a Unix subsystem, and the OS is not too bad, but my personal opinion is that Microsoft are doing a better job at the moment when it comes to stability and speed of the operating system. I have had various problems with various versions of MacOSX, and it irks me that these are happening on the very limited and overpriced selection of hardware which Apple uses. The move to Intel hardware was a good one (PPC = evil), but the unwillingness of Apple to indulge system builders out-of-the-box is irritating. Sure, you can build a hackintosh, but what you get is the worse OS (in my view) in a worse looking box (again, in my view).
One aspect of the Macbook Pro I absolutely love is the high def matte screen. Yes, you pay a lot more for the mac, but in some areas they really are good.
If I was buying for myself, I'd get a PC with Win7 on it.
For reference, I use Microsoft Security Essentials (free from M$) on my machine at home and have had no problems with viruses since I built it over a year ago. I have used a variety of paid-for antivirus software in the past, and found them slower than Security Essentials (although just as effective).
I also do a lot of photography and music, and find myself doing these on the PC more and more - especially now I have reaper (although I think you can also run that on a mac, but I've not bothered as my firewire box just sits on my PC at home).
I've not seen too much M$ advertising, but what I've seen from Apple really really annoys me. They seem so smug and eager to tell my why M$ is so bad. Sorry, but I wouldn't spend my own money on a company like that out of principle :) I realise I'm a freak in this regard though!
Roo
