Nice thread, Tom!
My favorite ads are, "Component XYZ, 'nuff said!" No, I beg to differ. Please say something more than that.
I will caution that the assertion that one who is sloppy with the writing of their ad will be suspect in the care of the gear as well. While I also get the same feelings in reading an ad, some of the biggest slobs I know write fantastically good ads here - with pictures and all.
However, most suprising is that the cleanest, most careful, fastidious person I know, and truly both the most generous and gentlemanly, writes absolutely dreadfully poor ads. He freely admits he doesn't feel comfortable constructing an ad, or even selling gear. What's more, he is so worried about not giving someone a great deal that he prices and grades the stuff he sells so low that were I not a friend of his who knows his gear well, I'd wonder about the condition of what he was selling. Thank goodness the pictures show the pristine condition of his equipment, but I still think the photos convey everything. Teaches me not to judge the book by the cover...