Dune

Finally, I've finished reading Dune. All the 6 books that compose the original series. Though, especially when the formula is near the same: the first 4/3 are composed by lot's of dialogs, almost all taken at one or two main locations (depending on how much groups of people are), and the last 1/4 is ruled by a critical period (war, coup d'etat, an assassination), where the action takes place.
With these words it looks I'm diminishing the quality of the books, but the truth is far from that. Yes, there are boring parts, and or you have an excellent dialog, or a boring one. But the excellent ones far outstand the poor. Dune books are more of an political-philosophical treaties than sci-fi (at least for me). Albeit there are strange ideas, often involving some kind of human supernatural power or abilities (not paranormal, the characters supposedly acquire these capabilities with, well evolution in learning methods), the only true sci-fi thing is the Holtzman theory that is applied to almost anything.
I think there are things that were added later, that may be a bit incongruent with the first book and the others, like the powers of the Bene Gesserit (and even Paul), which in the first book aren't all explained/declared.
Cutting the cheap talk, here are sentences of the first book that I liked allot:

A process cannot be understood by stopping it. Understanding must move with the flow of the process, must join it and flow with it.

Most educated people know that the worst potential competition for any young organism can come from its own kind.

There is no escape - we pay for the violence of our ancestors.

"He who can destroy a thing has the real control of it," Paul said. "We can destroy the spice."

The second book, 'Dune Messiah':

Power tends to isolate those who hold too much of it. Eventually, they lose touch with reality... and fall.

'God Emperor of Dune' :

Enemies strengthen you. Allies weaken.

'Heretics of Dune':

Bureaucracy destroys initiative. There is little that bureaucrats hate more than innovation, especially innovation that produces better results than the old routines.

When strangers meet, great allowances should be made for differences of custom and training.

'Chapter House Dune':

Religion (emulation of adults by the child) encysts past mythologies: guesses, hidden assumptions of trust in the universe, pronouncements people made in search of personal power, all mingled with shreds of enlightenment. And always an unspoken commandment: Thou shall not question!

"Humans can balance on strange surfaces," Odrade said. "Even on unpredictable ones. It's called 'getting in tune'."

Seek freedom and become captive of your desires. Seek discipline and find your liberty.

Ultimately, all things are known because you want to believe you know.

The Hitchhiker's Guide to the Galaxy: The Towel

Just about the most massively useful thing any interstellar Hitchhiker can carry. For one thing it has great practical value:

1. You can wrap it around you for warmth on the cold moons of Jaglan Beta;
   
2. sunbathe on it on the marble beaches of Santraginus Five;
3. huddle beneath it for protection from the Arcturan Megagnats as you sleep beneath the stars of Kakrafoon;
4. use it to sail a mini raft down the slow heavy river Moth;
5. wet it for use in hand to hand combat;
6. wrap it round your head to avoid the gaze of the Ravenous Bugblatter Beast of Traal, which is such a mind bogglingly stupid animal, it assumes that if you can't see him, he can't see you;
7. and even dry yourself off with it if it still seems clean enough.