Then instead of than
"PIN number" (the N already stands for number)
X "a.m. in the morning" (similar issue)
"baited breath" (unless you've been eating worms)
"very unique" (see "one of the only", in a previous post)
X "peaked my interest" (unless your interest began to decline after that)
"forward" instead of "foreword"
apostrophes -- some missing, others unnecessary

These things don't bother me so much from everyday punters (we all have our strengths and weaknesses; just because spelling & grammar always seemed to come pretty easily to me (perhaps because I read a lot as a kid) doesn't mean everyone else finds them easy), but when I see them in books/magazines/newspapers or hear them on radio or TV, I really feel that someone should have caught it before it was published/aired -- aren't proofreaders/editors/subeditors supposed to notice such things?

Although... it seems that businesses rarely think it worth the time to proofread things these days -- after all, "time is money"!
I'm a graphic designer, and in more than one job I've had, it has not been appreciated when I've caught mistakes; I've been told it's not my job to worry about such things. One printer even said that mistakes were no bad thing (as long as the mistake was the client's rather than ours), since they generate more business when the job needs to be reprinted... [sigh] Let's not worry about the sheer waste of binning all that paper and ink from the first run...