Macs are not immune to virsues, actually. There is a huge Mac botnet going around right now, and users are unable to defend themselves against it due to most Mac users not having an anti-virus.
The hardware isn't really "top of the line", it's not much different from PC hardware at all. If you're buying a PC, drivers are never an issue. That's only rarely an issue when building a computer yourself, and that's much more common in hackintoshes than PCs. Also, if you're buying a computer with 4+ GB of RAM, it will always ship with 64 bit versions. Apple does the same, putting 32 bit versions on computers with less than 3 GB of RAM, and 64 bit on ones with more. iLife being better is just your opinion, I prefer Office over OpenOffice or iLife, and there are better alternatives to things like iMovie and Garage Band anyway.
The concept of more stable isn't always true. Honestly, you have to make Windows crash yourself, it hardly ever happens on its own. Like I said, I used Windows for 3 years and only got one crash, and that was because I fucked something up when putting in new memory.