1: I find it to be quite intuitive, but to each their own. I can generally get more work done in the same amount of time on OS X than I could in Windows, not necessarily a huge amount more, but more none the less.
3: Although my XP systems were/are very stable, what irritated me the most when I was using XP was that all too often, if an individual program crashed, the whole OS would go down enough that a restart was necessary. As time went one this became less of an issue, but it persisted. On OS X, I almost never (we are talking less than 1% of the time) have a program crash and then take down everything else. Since I run a lot of beta software, crashes are to be expected on any OS, but in OS X those crashes do not affect the OS as a whole.
4: I really have nothing to say here since you seem to have your mind made up, which is fine, I have my mind made up as well.
5: I agree, there is no reason for a person with an iota of common sense to be able to surf the web without fear of viruses. Since I am on a platform that has reduced marketshare, and any other reasons for virus freedom, I can surf the web with extra super impunity.
I was basically in the exact same camp as you when I got my MacBook. I got it because I was going to be studying Software Engineering and we had to have laptops, and the MacBook seemed the most versatile for the price and size. I had always intended to use OS X, but never as my primary OS since I was much more used to Windows. However, for the first month or so that I had it, I was unable to install Windows at all for whatever reason, so I was 'forced' to use OS X. I ended up really liking it, and now it is my OS of choice, and Apple is my system maker of choice, mostly because I feel that their prices are generally decent, albeit at times more than competitors, and they are the only ones that can legally ship OS X.