Descriptions and impressions of Rivendell
From The Silmarillion:
"In all the days of the Third Age, after the fall of Gil-galad, Master Elrond abode in Imladris, and he gathered there many Elves, and other folk of wisdom and power from among all the kindreds of Middle-earth, and he preserved through many lives of Men the memory of all that had been fair; and the house of Elrond was a refuge for the weary and the oppressed, and a treasury of good council and wise lore." (The Silmarillion, 'Of the Rings of Power and the Third Age')
"In two domains the bliss and beauty of the Elves remained still undiminished while that Age endured: in Imladris; and in Lothlórien." (The Silmarillion, 'Of the Rings of Power and the Third Age')
From The Hobbit:
"His house was perfect whether you liked food, or sleep, or work, or story-telling, or singing, or just sitting and thinking best, nor a pleasant mixture of them all. Evil things did not come into that valley." (The Hobbit, Chapter 3)
"A little sleep does a great cure in the house of Elrond." (Bilbo - The Hobbit, Chapter 19)
"Weariness fell from him soon in that house, and he had many a merry jest and dance, early and late, with the elves of the valley." (The Hobbit, Chapter 19)
From The Lord of the Rings:
"'Rivendell"' said Frodo. 'Very good: I will go east, and I will make for Rivendell...' He spoke lightly, but his heart was moved suddenly with a desire to see the house of Elrond Halfelven, and breathe the air of that deep valley where many of the Fair Folk still dwelt in peace." (The Fellowship of the Ring, Book I, Chapter 3)
"It's a big house this, and very peculiar. Always a bit more to discover, and no knowing what you'll find round a corner. And Elves, sir! Elves here, and Elves there! Some like kings, terrible and splendid; and some as merry as children. And the music and the singing..." (Sam - The Fellowship of the Ring, Book II, Chapter 1)
"Sam led him along several passages and down many steps and out into a high garden above the steep bank of the river. He found his friends sitting in a porch on the side of the house looking east. Shadows had fallen in the valley below, but there was still a light on the faces of the mountains far above. The air was warm. The sound of running and falling water was loud, and the evening was filled with a faint scent of trees and flowers, as if summer still lingered in Elrond's gardens." (The Fellowship of the Ring, Book II, Chapter 1)
"Evil things do not come into this valley... We are sitting in a fortress. Outside it is getting dark." (Gandalf - The Fellowship of the Ring, Book II, Chapter 1)
"This is the Hall of Fire ... here you will hear many songs and tales - if you can keep awake. But except on high days it usually stands empty and quiet, and people come here who wish for peace, and thought. There is always a fire here, all the year round, but there is little other light." (Gandalf - The Fellowship of the Ring, Book II, Chapter 1)
"Time doesn't seem to pass here: it just is. A remarkable place altogether." (Bilbo - The Fellowship of the Ring, Book II, Chapter 1)
"For a while the hobbits continued to talk and think of the past journey and of the perils that lay ahead; but such was the virtue of the land of Rivendell that soon all fear and anxiety were lifted from their minds. The future, good or ill, was not forgotten, but ceased to have any power over the present" (The Fellowship of the Ring, Book II, Chapter 3)