All those patches, virus definition updates and system crashes seem like distant memories. I vaguely remember all those "Dummies" books that used to cram my bookshelf, that showed me how to do Registry updates, scan and defrag hard drives, recover corrupted system files, etc., etc.
I don't need any of those anymore.
I use Apple, Microsoft, and open source (e.g. Linux) products interchangeably every day at work and home, and to be honest, they're all pretty solid these days.
I disliked having to deal with the older Windows versions (XP and prior) because they were not fundamentally solid and secure -- security had been bolted on as an afterthought. On my home systems I switched from Windows to Linux around 2001, back to Windows in 2003, then to Macintosh in 2005, and have stayed with Macs since then -- but I have both Windows (7) and Linux running alongside OS X in virtual machines for those programs that require Windows.
Done properly, Windows 7 can be made very secure and it stays pretty fast even with anti-virus installed. I've got it running in another window on my Mac Mini even now...
However, if you're happy as a Mac user I wouldn't suggest you switch -- after all, I'm writing this on OS X. :)