I cannot stress it enough!!! It won't catch all things (like, leaving off the s in she - he is still correct to SpellCheck!!!!!), but it will save so much time & effort. I love Spell Check.
I also love my Thesaurus. I don't worry about variety the first time around as I hand write my stories, but when I putting it all into the computer, Mr. Thesaurus is right there with me!
In the book world, I discovered today that the bulk of YA fiction is put out by three big publishers. Oh, they may list another company, but it's always a division of a bigger one in New York.
I did find that one of the biggest Christian publishers is based out of the town I was born in, Eugene, Oregon. How about that?
Learn something new every day ...