The True Hero of The Lord of the Rings

[Guinevere]

I agree with what most of you wrote, that there is no single hero but many heroes in LotR.
But as for the main character... I can't decide between Frodo and Sam. In any case the whole tale is seen with the eyes of the hobbits! In the beginning, certainly I see Frodo as the main character. It maybe as Lyta says, that in the last part of the book Sam "takes over" because we wouldn't be able to follow Frodo. But on the other hand, as Lindil wrote, Sam is really the character with whom we can relate best. None of the others reveals so much of their thoughts or feelings.
As early as 1944 Tolkien wrote in letter #93:

"Certainly Sam is the most closely drawn character, the successor to Bilbo of the first book, the genuine hobbit. Frodo is not so interesting, because he has to be highminded, and has (as it were) a vocation. The book will probably end up with Sam. Frodo will naturally become too ennobled and rarefied by the achievement of the great Quest, and will pass West with all the great figures; but Sam will settle down to the Shire and gardens and inns.