Journal: by bytesmythe (58644)

Obvious
there / their / they're
to / too / two
your / you're
whose / who's
its / it's
lose / loose
which / witch
then / than

Others
incorrect: ya'll
correct: y'all

incorrect: run the gambit
correct: run the gamut

incorrect: for all intensive purposes
correct: for all intents and purposes

incorrect: suppose to
correct: supposed to

incorrect: could of / should of
correct: could have / should have

incorrect: explicative (referring to profanity)
correct: expletive

Common Mispronunciations
incorrect: simular
correct: similar

incorrect: nucular
correct: nuclear

incorrect: mute point
correct: moot point

incorrect: mischievious
correct: mischievous