Hermione tapped her chin. "Well, if you think about it, the best house would be Hufflepuff, especially for a true Slytherin, according to the traits you just described," explained the brainy about-to-be-sorted firsty.
Draco sneered. What would a mudblood know? He was a Slytherin in all but blood! Like his family before him!
"You're totally right," chimed in Harry Potter, the infuriating Half Blood that had defeated the Dark Lord. "I mean, they WOULD make the best minions out of all four houses. They're supposed to be hard working and loyal, so they're unlikely to backstab you and they'll probably work hard in your name, so you'd be set. All you would have to do would be earn their loyalty," reasoned the Boy Who Lived.
Really, Draco didn't know why he'd offered his hand in friendship to the half blood, because he hadn't even gotten the chance to explain why Slytherin was a better house before his mother pulled him away. Fortunately for him, Harry hadn't seen his mother force him to crossdress. It didn't matter that she'd always wanted a little girl or that Draco did, as a matter of fact, pull off a sundress like no one's business, it still stung his pride. His father and godfather pretending not to laugh didn't exactly help when they sucked major balls at it.
The half blood had a little more weight to his words in Draco's mind, and it allowed him to check them through, analyzing both his and the mudblood's arguments for why a real Slytherin would be in Hufflepuff. Neither Crabbe nor Goyle were following the conversation, both absorbed in staring at nothing.
So as the mudblood and Potter chatted away (oh, how he hated his father's instructions to befriend Potter, as they forced him to harbor a mudblood in HIS compartment!), he sat down to contemplate his sorting.
"And that is, more or less, his justification for being a Hufflepuff. Apparently, the sorting hat thought it would be funny and so allowed it," explained Narcissa, putting down her son's letter with more than a bit of distaste, looking at her husband, expecting to see him sneer in rage, only to find him... weeping?
"I'm so proud of my little boy!" gushed Lucius, grabbing a napkin to wipe the tears flowing from his eyes. "He's already a little manipulator!" he added, sniffing and then cleaning his nose rather loudly.
Narcissa was mystified, but, like many other things she saw Lucius do, she decided not to question it.