This is a very intersting thread

Harry: 5'10 (1.77 m) - I think he is smaller than 5'11 because of a statement he made when he transformed in Runcorn.
Ronald: 6'1 1/2 (1.86 m) - Seems pretty fair to me
Hermione: 5'5 (1.65 m) - Just like Emma Watson

Albus Dumbledore: 6'2 (1.88 m) - I think he is smaller than Riddle
Lord Voldemort: 6'3 (1.91 m)
James Potter: 5'10 (1.77 m)
Lily Potter: 5'5 (1.65 m)
Remus Lupin: 5'9 (1.75 m)
Peter Pettigrew: 5'3 (1.60 m)
Sirius Black: 5'11 1/3 (1.81 m)
Ginny Weasley: 5'1 (155 m) - he is described as small by Fred and George
Neville: 5'8 (1.75 m)
Fred: 5'11 (1.80 m) and George 5'11 (1.80 m) - There are a quote from JK who says they are taller than Harry
Draco: 6' (1.83 m)
Dean Thomas: 6'3 (1.91 m)
Seamus Finnigan: 5'7 (1.70 m)
Luna Lovegood: 5'4 (1.62 m)
Bellatrix: 5'11 1/2: (1.81 m, wow, she's taller than me :Bl)
Narcissa Malfoy: 5'8 1/2 (1.74 m) - She is described to be as tall as 16 years old Harry...
Lucius Malfoy: 6' (1.83 m)
Molly Weasley: 5' (1.52 m)
Arthur Weasley: 6'2 (1.88 m)
Tonks: 5'7 (1.70 m)
Alastor Moody: 5'9 1/2 (1.76)
Kingsley: 6'2 1/2 (1.89 m)
Dudley Dursley: 6'2 (1.88 m)
Vernon Dursley: 6'1 1/2 (1.86 m)
Petunia Dursley: 5'6 (1.68 m)
Severus Snape: 5'7 1/2 (1.72 m) - described as a bit small
Dolores Umbridge: 4'9 (1.44 m) - lol
Rubeus Hagrid: 8'6 (2.60 m)