It's been a year or so sinceI last picked up a Heinlein novel. My fav of fav's has always been Starship Troopers (the movie was a travesty), but the Lazarus Long stories are a close second. Lazarus may have been my first real exposure to the idea of kilts as well.
I first discovered Heilnlein when I was 13 or 14, and being an extremely ravenous reader I rapidly read all of his books. I wish I'd had a chance to meet the man, he must have been an interesting one to talk with. He died while I was still in High School...