i would like to commend those who have optical mice - they are far better than ball mice. (although that is sometimes a matter of opinion)
my optical mouse, Microsoft (if i could scrape it off without scratching the mouse, i would.) Intellimouse 5button, and it works fine on our fluffy carpet (lots of different colours), just like when its on my multicoloured desk without a mousepad, its just a little bit slower than normal. so to all the people saying that optical mice arent that great, check you're sources.
This mouse is at least 1 and half years old. so its not an awesome new one. I think its the first thing microsoft actually made that was worth paying for