I don't like mario 64 just because of the sheer length of the game. (I have been playing for three years and hav like 50 stars) (and the youtube stuff I will not name)
Don't let the YouTube shit affect your opinion. Besides, when you collect all 120 stars, all it does is unlock a cannon that shoots you on top of Peach's Castle to meet Yoshi, who brings you to 100 lives and then leaves.
QUICK QUESTION FOR ALL OF YOU. IF YOU HAVE EVER PLAYED A SUPER MARIO GAME, WHAT IS YOUR FAVORITE MARIO GAME THUS FAR? BEFORE YOU ASK, MY FAVORITE IS EASILY SUPER MARIO 64.