It's Blaise Zabini.
I loathe you if you love Muggles,
He hated Muggles and Blood traitors, as he once expressed his intense disgust for Ginny despite her being pretty, for the same reason.
But oh well! Neither do I care much if you don't.
He never had much respect for anyone. In fact, he ridiculed Draco when Lucius was outed as a Death Eater.
Hard luck, if you wish to please me,
As approval is something, I give won't.
As said by Pansy, it was incredibly hard to impress him. Plus, he never thought highly of even his fellow Slug-Club members.
Wealth, I inherited - in multifolds, in fact,
Suspicious though, it may seem.
Through the deaths of the seven husbands of his mother, all under suspicious circumstances.
And a trivia now - I played a bigger role in a movie,
Than it was originally deemed.
In Deathly Hallows Part 2, instead of Crabbe, it's Zabini who accompanies Goyle in the Room of Requirement. Whatever happened to Crabbe in the book happened to Goyle, and whatever happened to Goyle in the book happened to Zabini. The reason for this being, Jamie Waylett who played Crabbe was arrested for culture and possession of marijuana in real life.