this is important issue when you have a multi-language windows (like me is the english version with chinese support) and you are a web developer.
I always did web development in English but my software always automatically encoded in big-5 and I have to change it to UTF-8
So, one day I came across a problem where my site is not working in IE7. I have been trying to correct it for 5 hours still no solve. At last, I found the problem where when I view the source of the page, I saw the first character on first line of the source codes is a dot.
I then solve this issue by encoding my php file which came on top all time of every index.php to UTF-8 without BOM (means UTF-8 without signature in some software).
Really headache huh!