Dr. No was the first Fleming I read at the tender age of nine back in the late 60's. I remember my Mum was horrified when I bought home this tatty paperback copy (it was the film tie-in) which a friends father gave me. I can't pretend then I could understand everything but it was an amazing experience. By my mid teens I had read them all but Dr. No still remains my favourite book. There is such sense of nostalgia attached to it for me.
Finished Dr. No a few days ago. Absoloutely amazing. I thought From Russia With Love was great, but Dr. No has got to be the best one so far in my opinion. Fleming writes about Jamaica in such detail that it's just an absoloute pleasure to read. I loved the assault course, too. Wouldn't mind seeing that properly adapted for a future movie.
Doctor No is definitely in the top tier of Fleming's books for me, too. I was in my early teens when I began to read the Fleming books (and I started the films at the same time). I'm generally a slow reader but I recall how DN (and LALD) seemed to fly by! I think I may have reread DN the most times out of all of them as well. It's so evocative and the action scenes and characters are wild. There's nothing to dislike, IMO.