When talking with some of my fellow "wordies," we often express dismay that spell check has removed the incentive to learn how to spell.
I'm certainly grateful for spell check, because it saves a trip to the bookcase to pull out the dictionary. But all those lists of vocabulary words in grade school, participating in spelling bees (I won in third grade! I spelled rheumatism.), reading and learning about various words...was it all for naught?
Well...I don't think so. While spell check is a powerful tool, it doesn't take homonyms into account, and it is no substitute for proofreading. (One of my common typos is typing "and" instead of "an." The former happens to be a fairly common word. <grin>) Spell check will let such things as the improper use of as "to" and "too" slide, not to mention "their" and "there." There are many more. Spell check does not erase all errors, and is not a panacea for not knowing the fundamentals of grammar or spelling.
Of course, if you're going to rely on spell check, I suggest you actually use it. I recently came across the word "surroget" in my readings. You can't blame spell check for that one!