Anyway, check out this article... What Your Favorite Dead Song Says About You.
For me it's Casey Jones and Shakedown Street.
For Shakedown Street, I guess that I dig Disco Dead and of course, everyone knows that Shakedown is the headiest place to score at any big show. And Casey Jones? That was one of the first Dead songs I ever heard in heavy rotation on the classic rock radio station when I was growing up in NYC.