Suggestions by @jameshook

Jonathan Ross

as Sorting Hat in Harry Potter (Perfect Casting)

Score: +3

Tom Glynn-Carney

as Draco Malfoy in Harry Potter (Perfect Casting)

Score: +1

Maisie Williams

as Hermione Granger in Harry Potter (Perfect Casting)

Score: -4

Stephen Fry

as Professor Albus Dumbledore in Harry Potter (Perfect Casting)

Score: -3

Ian McKellen

as Professor Albus Dumbledore in Harry Potter (Perfect Casting)

Score: +10

Sophie Turner

as Ginny Weasley in Harry Potter (Perfect Casting)

Score: -5

Ralph Fiennes

as Lord Voldemort in Harry Potter (Perfect Casting)

Score: +7

Tim Curry

as The Bloody Baron in Harry Potter (Perfect Casting)

Score: +6

Maggie Smith

as Professor Minerva McGonagall in Harry Potter (Perfect Casting)

Score: +6

Ben Barnes

as Sirius Black in Harry Potter (Perfect Casting)

Score: +34

Rupert Grint

as Ron Weasley in Harry Potter (Perfect Casting)

Score: +6

Aaron Taylor-Johnson

as Harry Potter in Harry Potter (Perfect Casting)

Score: -16

Tom Hardy

as Fenrir Greyback in Harry Potter (Perfect Casting)

Score: +4

Robbie Coltrane

as Rubeus Hagrid in Harry Potter (Perfect Casting)

Score: +7

Alan Rickman

as Professor Severus Snape in Harry Potter (Perfect Casting)

Score: +21

Richard Harris

as Professor Albus Dumbledore in Harry Potter (Perfect Casting)

Score: +11

Helena Bonham Carter

as Bellatrix Lestrange in Harry Potter (Perfect Casting)

Score: +59

Rik Mayall

as Peeves the Poltergeist in Harry Potter (Perfect Casting)

Score: +6

Hugh Grant

as Gilderoy Lockhart in Harry Potter (Perfect Casting)

Score: +4