What spelling errors annoy you the most?
For me, it's the ones that people could avoid if they just thought for half a second about what the word meant.
"Rediculous" bugs me, in part because it it's so damned common. You almost never see people misspell "ridicule". Describing something as "ridiculuous" says that they are "worthy of ridicule", not that they're "doubly diculous".
Oh, and there's a difference between a "typo" and a "spelling error". A "typo" is a "typographical error", an error that occurs because of the mechanics of data entry. "Teh" instead of "the" is a typo. CApitalizing the first two letters of a word instead of just the first is a typo. It's a matter of your fingers tripping over the keys. A "spelling error" is in the wetware.
As I was typing this, I caught a related error in someone's description on a MUCK: "taunt" instead of "taut". That's not a typo or a spelling error. That's just using the wrong word. So... you have a "taunt rear." Does that mean your rear is making fun of me, or that I should make fun of it?
'Cuz I'm doing the latter.