If it were not be for Frodo, then there would not be a Lord of the Ring Trilogy. As for Arwen and Eowyn, they were great too. Boromir was a honorable man in the end and he had a great role in Fellowship.
My Least Favorite would be Denethor too for he hurt Faramir馃檨 and he is such a tyrant. Grrrrrrrrrrrrrrrrrrrrr...LOL