The most confused homonyms in the English language:

  1. Their, There and They're

  2. To, Too, Two

    • to = in the direction of
      She went to her house.

    • too = also; in addition
      I want a soy patty too.

    • two = whole number between one and three
      Two rabbis and an ostrich walked into a pub...

      All together:

      Mitchevious wanted to get two soy burgers too.

  3. Whether, weather

    • weather = climate
      Oh, the weather outside is frightful, but the fire is so delightful.

    • whether = if
      I'm cooking you a soy pie whether you want one or not.

  4. Accept and Except

    • accept = to take or receive
      Please accept our apologies for pouring coffee on your motherboard.

    • except = leave out
      You're all welcome, except for the slashdot troll.

      All at once:

      Witchiepoo decided to accept the offer except for the soy tea.

  5. Whose and Who's

    • whose = possessive form of who
      Whose soy burger is this?

    • who's = contraction for who is or who has.
      Who's going to visit --OutpostMir-- in the insane asylum?

  6. Its and It's

    • its = possessive form of it
      Watch EDB was its tail after he borges someone.

    • it's = contraction for it is or it has
      It's beginning to look a lot like Christmas.

  7. Your and You're

    • your = possessive form of you
      May I borrow your soy?

    • you're = contraction for you are
      You're an Everything2 addict.

      All at once:

      You're welcome to bring your soy beer to the party.

  8. Affect and Effect

    • affect = an emotion; to have an influence
      I don't know why I'm crying, reading that node seemed to really affect me.

    • effect = a result; to cause to happen
      The Soy-O-Tron failed to have the desire effect on Yurei.

Thanks to The Everyday Writer for the info.