Again, if you've got a virus you did something wrong. I have run Windows machines successfully for many years with no antivirus software whatsoever. They are connected to the internet and guess what? No viruses.
If you don't get the spinning beach ball then you mustn't be a user of iTunes or iPhoto. Those programs are the worst for it.
I'm just wondering when you last used Windows. There was a time when it was terrible but Microsoft has really improved XP and Vista, and it looks like Windows 7 is going to be even better. They are rock solid.
Since when what? Look at your dock - it doesn't list what windows are open, it just has an icon and an indicator showing what program is open. Compare that to the Windows task bar, which shows exactly what windows are open as well as what programs are open. For example, if you have two web browser windows open, on Windows you can see them both without clicking anything. On OS X you simply can't.
I don't believe either to be superior. I just don't like seeing people attacking Microsoft when they are doing exactly what Apple did in the past with their ridiculous "Get a Mac" ads.