I can't believe that President W. Bush's advisers never corrected his pronunciation of "Nucular". I'm sure that he stuck to it just because changing would be an admission that he was wrong.

Some words ARE pronounced differently in different places. Most Americans say, "ve-hick-les", while in Canada, the "H" is silent - "Ve-ick-les".

My pet peeve has already been mentioned:"I could care less." This is an almost useless statement. A person who cares a little bit could care less and a person who cares very much could care less.
All it tells me when someone says,"I could care less," is that they DO care. It doesn't tell me how much they care.

I thin of Mondegreens as describing misheard lyrics to songs. For the song Mr. Bojangles The Nitty Gritty Dirt Band sang Jerry Jeff Walker's line, "And he spoke right out," as "And the smoke ran out." When they sing the song in concert these days, they use Jerry Jeff's original lyrics.