If you are into shows like Battlestar Galactica and Firefly, you should try the Grimspace series by Ann Aguirre and The Native Star series by M.K. Hobson.
If you are into British humor and tons and tons of puns and literary jokes, you should try the Thursday Next series by Jasper Fforde. (I also absolutely recommend his work, Shades of Grey!)
If you like the feeling of laying on your back in water in direct sunlight, you should read Raw Blue by Kirsty Eagar.
If you like the movie Heathers, you should read Fury by Shirley Marr.
If you like the worldbuilding in shows like Merlin and want to feel immersed in a world, you should try Seraphina by Rachel Hartman, any books by Tamora Pierce, or anything by Brandon Sanderson.
If you like books about rehab and are looking for great LGBT YA lit, you should try Suicide Notes.
If you like being dropped down in the middle of a community and following large casts of characters, you should read any of Maeve Binchy's books. (I recommend Tara Road, Circle of Friends, Light A Penny Candle, Firefly Summer, and Minding Frankie)
If you want to read some great short stories (for free! online!), you should try Harrison Bergeron, The End of the Party, Ponies, All Summer in a Day, and 2BRO2B.
If you like MMORPGs, you should read Ready Player One by Ernest Cline.
If you like zombies and politics (there are some of us out there!), you should read the Newsflesh books by Mira Grant.
If you like Nora Roberts books but wish they were a little sexier, you might try Susan Elizabeth Phillips. (try Kiss An Angel)
If you like Doctor Who, you might like Walls of the Universe by Paul Melko and Replay by Ken Grimwood.
If you are an teen/adult who liked the tone of The Hunger Games, you should read Stephen King's The Running Man and The Long Walk.
If you still think Penny from Inspector Gadget deserved to be recognized as the brains behind the operation, you might like What Was Lost by Catherine O'Flynn.
If you liked The Thirteenth Tale, you should try The Vanishing Act of Esme Lennox by Maggie O'Farrell.