I don't spell too well. I use to be an average speller, or better, but with the advent of spell-check I emptied out the memory cells in my brain that were used for spelling so that I could put other things in them. I have a limited number of memory cells left.
The TW spell-check doesn't work too well for me. It doesn't always understand my sophisticated vocabulary, and simple punctuation -- such as apostrophes -- can throw it off. If I want to make sure I'm spelling something correctly, I use dictionary.com, Webster's, or skeezix.
When I was a kid, if I used a fairly sophisticated word in conversation my dad would say "Spell it." And if I couldn't he would say "You shouldn't use words that you can't spell." Not the best advice he ever gave me, but now that communication is increasingly in written form, I see a bit more sense to it. Don't you ever get an email from someone you think is rather intelligent that is just peppered with misspellings, and then your evaluation of their intelligence drops a few points? Don't feel bad if you can't spell though. I've found that spelling is not highly correlated with overall intelligence.
Man I need a TV when I've got Tourette's