According to people I know who work in web development, IE10 is actually ahead of Firefox right now, and actually competes with Chrome on some benchmarks.
That said, if you're using IE6 or something like that, please never do that again, and make sure it is wiped from your hard drive forever. Using IE6 is like a crime against the Internet.
--
Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision