by highsorcerer » Monday 30 June 2003 3:24:45am
Percy has shown qualities of both Gryffindor and Slytherin. He was brave enough to reject his entire family for what he thought was right. However, he is also a pure-blood (Slytherin quality), and has unfettered ambition, which also seems to be a Slytherin quality. He may have been sorted into Gryffindor because while he has ambition, he has no ambition to get there using dark arts. Interestingly, despite being pure-blood, ALL the Weasley's have been sorted into Gryffindor. Muggle-lovers probably don't qualify as pure-blooded enough.
Sirius obviously hated his family. He definately lived in a Slytherin house (snake doorknobs and all), and is another pure-blood. The portraits all hated him, considering him to be a disgrace, probably because he rejected Slythering and everything it stood for. So in his own way he was brave enough to stand against his family. Like Harry, he was probably offered a choice and firmly rejected the Slytherin path.
Peter is a different case. We don't know if he's pure-blood or not, and he's never shown any kind of bravery. He always wanted bigger and badder friends around (first the Mauraders, then Voldemort). We don't even know really if he was sorted into Gryffindor. In fact, JKR hasn't ever come out and said what house the Mauraders were in (though in the first film, James is listed as a Gryffindor seeker on the plaque, and JKR had enough control to move to strike anything that would be contradictory).
Voldemort is an odd case. While in the film CoS, Tom Riddle is clearly displaying a Slytherin patch on his robes, he would seem an unusual choice for Slytherin sorting, as he's not pure-blood (technically, Harry is, since both his parents were wizards, though he's only one generation removed from muggles). His temperament was clearly Slytherin, and the fact he's a direct heir of Salazar Slytherin probably tipped the balance).