Of the four Hogwarts houses, many would say Slytherin is the most misunderstood. As true as it is that Slytherins have many overlooked good qualities, there is one house that gets a really bad rep.
In Harry's first year, Draco Malfoy says on the train that if he were to be put in Hufflepuff, he would go home.
The Sorting Hat describes Hufflepuffs as loyal friends and hard workers. It is said that they're also particularly good finders.
Many Hufflepuffs today face discrimination (from Gryffindors especially), but they are some of the most beautiful personalities in the Potterverse.
During the Battle of Hogwarts, Gryffindors and Ravenclaws and even some of the Slytherins all fight the Death Eaters because it's the right thing to do, because Voldemort is evil. Hufflepuffs, however, are often in the front lines. They fight for those whom they love. They're the protectors. One of the best things I've heard said about Hufflepuff pertaining to the Battle of Hogwarts is that "they fought not because they hated what was in front of them, but because they loved what was behind them."
Loyalty and hardworkingness are powerful virtues often overlooked by brain and brawn. I hope after reading this, all of you will think twice before saying Gryffindor is your favourite house.
(P.S. - J.K. Rowling is a Hufflepuff. And she's perfect.)