I found this when I was questioning to use 'taken aback' or 'taken back,' and looked them up together on Google. It seems really useful, and actually simply quite interesting. Brian's List - Common Errors in English
Yes, this site is in my Favorites, and I also have a link to it in my own website. It is a great site to help you avoid common usage blunders, like mute point instead of moot point, and loose instead of lose when you mean the antonym of win.
