Bonnie:

I think you can decline the updates from MS, and you can even turn off the automatic check for updates, doing it manually when you feel like it instead.

JTT:

The issue with almost ALL websites that are Windows-biased is not the Mac, but the browser. Firefox tends to do better in this regard than Safari. For extreme measures I keep a copy of Internet Explorer available, just in case, but hardly ever have to call on it. I believe this traces to the market-grab M$oft built using their proprietary altered Java set instead of the universal Java standard from Sun, but I could be wrong there. But as more and more people discover the delights of the Mac this happens less and less often.
And web designed can easily work around this problem and more and more of them take the trouble to do so.

A