I disagree with him about "anxious" and "eager"--that's language change in action. In fact, Web11 lists "eager" as a synonym of "anxious" and lists one definition of "anxious" as "ardently or earnestly wishing." I have noticed, however, that UK speakers are far less likely to use the word that way.

Web11 also lists "flack" as an acceptable variant of "flak," though some will still disagree.

He should have added "lie" and "lay." I see those more commonly confused than any other words.
 

I was wondering what you'd make of that list.
 

The motherload:

http://www.wsu.edu/~brians/errors/