Recommend me some books!...Please.

Tolkien's books ( The Hobbit and the LOTR trilogy maybe? )

My brother said enders game is an amazing book.

If you haven't read it yet, John Dies at the End by David Wong is a very interesting horror/fantasy/ridiculous mashup. Lighthearted read, but a very worthwhile one. Strong language at times. I'm currently reading the sequel, This Book is Full of Spiders, and it looks to be even better.

I also heartily recommend Scott Lynch's The Lies of Locke Lamora. Not so much the sequel (mostly as I really didn't like the way it ended.) And of course Steven Erikson's epic fantasy series The Malazan Book of the Fallen. Those behemoths ought to keep you busy for a while.

I know there's a movie about it, but One Flew Over The Cuckoo's Nest is fantastic. Even if you've seen the movie, just go for it. The story is told from another perspective.

The same (kind of) goes to A Clockwork Orange. it has a different ending from the movie... Seems like Kubrick left off the most baffling turn-tail event from the film; it kind of gives it a new message if you ask me, but I loved the movie and the book too.

And then, finally I'll recommend Roadside Picnic, which is a short novel, and the basis for the movie STALKER and the S.T.A.L.K.E.R. game series, yet it tells the story of nothing like what's presented in the other 2. The movie is a bit too artsy, approach with caution; though I loved it.

any books based on the character of Jack Reacher who is an ex-army cop (author pen name Lee Child)

Ready Player One by Ernest Cline. Required reading for gamers imo and a wonderfully realised sci fi world.

the demonata series, the world of darren shan both by darren shan
the earth children series by jean m. auel
the wolf brother series (forgot the authours name)
the hatchet series (forgot the authors name again >.<)
the hunter's apprentice (may also go under the title the grey hunters) it is one of my favourite series
hmm other than that nothing really jumps up as a great reccomendation, i do suggest you state what age group your niece belongs to though so people can make appropriate suggestions (for instance the wolf brother series should be fine for people who are about 10 or 12 years and older but still enjoyable by adults)

The Name of the Wind - Patrick Rothfuss, really worth time ;]
Andrzej Sapkowski - The Witcher ( Wiedźmin )

The Witcher series, by Andrzej Sapkowski. A Song of Ice and Fire (series), by George R. R. Martin. The Green Mile, by Stephen King.

For your niece I think the Artemis Fowl series, by Eoin Colfer, or something by Cornelia Funke would be appropiate.

I am legend, m is for magic

The Power of One by Bryce Courtenay

Metro 2033 and 2034 or Lord of the rings

I'm not going to recommend you any high fantasy or sci-fi, because I don't read them much, but if you'd like to read something else, give a try to these:
Memoirs of a Geisha, Arthur Golden ;
Lolita, Vladimir Nabokov ;
The Art of War, Sun Wu ;
Wiedźmin (The Witcher), Andrzej Sapkowski

I recommend you read Hard-Boiled Wonderland and the End of the World by Haruki Murakami. It's a bit like the dreamlike Inception (a film I liked, btw) in its multi-layeredness and intricacy, just much better and bursting with wit, humour, imagination and emotional resonance, and all almost 25 years before that film. From the Amazon description: "Half the chapters are set in Tokyo, where the narrator negotiates underground worlds populated by INKlings, dodges opponents of both sides of a raging high-tech infowar, and engages in an affair with a beautiful librarian with a gargantuan appetite. In alternating chapters he tries to reunite with his mind and his shadow, from which he has been severed by the grim, dark "replacement" consciousness implanted in him by a dotty neurophysiologist. Both worlds share the unearthly theme of unicorn skulls that moan and glow. Murakami's fast-paced style, full of hip internationalism, slangy allegory, and intrigue, has been adroitly translated."

Or, for something quite different, how about The Sense of an Ending by Julian Barnes. From the Amazon stub: "A novel so compelling that it begs to be read in a single setting, The Sense of an Ending has the psychological and emotional depth and sophistication of Henry James at his best, and is a stunning new chapter in Julian Barnes's oeuvre." This book is a quietly devastating little masterpiece with one of the most powerful, jaw-dropping finales in recent memory.

You can try The Chronicles of Amber series, Lord of Light, A Night in the Lonesome October by Roger Zelazny.
Myth Adventures series by Robert Asprin if you want humorous fantasy. Also check some short stories by Robert Sheckley, some of them are awesome.

Well, i'm not going to read all the comments so if it's already listed, excusez moi :) You definitely should read the Geralt of Rivia saga, aka The Witcher :) Yoy may have heard of that videogame... The videogame is based on these books by Andrejz Sapkowski and they are AWESOME!

The Dark Tower series by Stephen King

Ringworld by Larry Niven

If you like fantasy, The Name of the Wind is excellent. There is a sequel to it out already called The Wise Mans Fear, and a third one is in the works. It was the authors first book and has been really well received as far as I know. For sci-fi, I haven't read this book myself, but my boyfriend has mentioned Enders Game as one of his favorites. (-:

Edit: The series is also known as The Kingkiller Chronicles. Looks like everyone beat me to it haha.

Good luck with your search, and I think I'm going to read a few of these books that have been recommended myself!

Mellenium series its a good trilogy of mystery/policial books i did enjoy it :)

I'm not sure if any of these have been said, I only scanned through the comments, so I apologize if this is redundant.

I don't read much fiction but I really enjoyed The Return of Merlin by Deepak Chopra and 1Q84 by Haruki Murakami.

Also, I love books by James Rollins. Two that stand out in my mind right now are Excavation and Amazonia. They have bizarre twists and intertwine fantasy with reality.

For your niece, depending on how old she is, she might be interested in George's Secret Key to the Universe by Stephen Hawking and his daughter Lucy Hawking. It has two sequels and combines the excitement of a young boy's adventure with some physics explanations (for children, of course.)

American Gods maybe

Metro 2033! I actually haven't read it yet haha but the game got great marks on its story and it's based on this book. So I assume if you like the game, you will love the book!

War and Peace by Leo Tolstoy

If you into SF, than try Foundation series, by Asimov.

The Kite Runner. The Fault in Our Stars. John Green/Neil Gaiman/Maureen Johnson/Scott Westerfeld books. The Casual Vacancy.