Incidentally, I just found a copy of the D&D Basic Set at Goodwill for about $3. The contents inside appear to be untouched! It even still has the dice and the crayon! Nowadays I'm playing D&D 3.5 (mostly as a GM for my 10 year old daughter and 13 year old son), and that is what my kids know, so...
My first adventure...back when I was 9 myself...I love it still, even though I've read and heard arguments about how much can be done to improve it...I think my most clear memory of it was that when my friends and I first tried it we had no idea that you were not supposed to read the ENTIRE room...