FOTR: Adventure, quickly, gripping, full of Hobbits hehe...
TTT: Battles, sounds and pics of honor and nobility of Rohirrim...
ROTK: Great 'FINALE', really gripping, emotional and the result of the great war 4 the Middle Earth...
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These 3 instalments are something GREAT as a whole.
So, the Tolkien's trilogy and Jackson's movie(s) are something that I will never forget. Also, LOTR trilogy as book is on my second place (right behind the saga of George R. R. Martin: A Song of Ice and Fire), and the movies are the best as I ever seen.