Frodo would have been screwed without Sam.but more importantly, I think Sam is the real hero of the story. Frodo had to carry the ring, but Sam carried Frodo.<--Samwise IS the real hero of the story according to Tolkien.
In The Fellowship, Gandalf says "If you're referring to the incident with the dragon, O barely had anything to do with it. I just gave your uncle a little nudge out the door." This picture is what he means by "nudge out the door"