What I will agree to is that Apple has better marketing and better advertising, and the fact that they're able to sell Intel equipment for much higher prices than their competition is more a tribute to P.T. Barnum's knowledge of human nature than it is to any real innovation: I've had Zunes and I've had iPod Touches and frankly, the Creative Zen -- which no longer exists -- was a better value than either.
I'll speak for myself: I got sick and tired of being paranoid about viruses. And even if you have an antivirus program, common sense tells you that for the AVP to have a virus in its database, the virus has to have been on the loose compromising machines for a non-zero period of time - so best practice cannot guarantee that your Windows box doesn't get hit. Hence, the paranoia, which actually increases your vulnerability to trojan attacks.A memorable line in a television play I once saw said, "100% safe, nothing is." But I'd rather take my chances on an industrial-strength OS (Unix) than on the Antivirus band-aid on an OS which was not designed from the ground up with the possibility of bad software in mind. I suspect Win7 will still have virus problems due to its compatibility with prior versions of Windows which notoriously did have that problem. And, antivirus costs computer cycles even if you get the software and database updates free.
Consequently I like the Mac. It costs more, at least on a first-cost basis, but I am satisfied with the value proposition. And obviously I'm not alone. Like any product which you pay more for, you are the more determined to get the value you paid for - and that means that Macs are kept in service longer (and also, admittedly, that an element of denial of anything which questions that value tends to creep into the owner's thinking. So be it; that process can also work the other way around).
As Apple market share increases, the number of exposed vulnerabilities will also. There are plenty of Unix exploits. Please have a look here. I have to deal with them on Unix systems on an (almost) daily basis. I love the ix variants, but anybody who is not patching routinely is vulnerable. I applied six patches to the Ubuntu 9.04 installation I am typing on at this minute just last night; and I apply patches to my linux box(es) every day, so it's not as if I was just catching-up.