There were well over 100 casualties in the wizarding world from the Second Wizarding War. An unknown number of muggles also lost their lives. Here is a rough list of the dead on both sides:
Order of The Phoenix, Dumbledore's Army, Ministry of Magic, and Allies: Cedric Diggory, Broderick Bode, Sirius Black, Emmeline Vance, Amelia Bones, Florean Fortescue, Mrs. Abbott, Igor Karkaroff, Montgomery, Albus Dumbledore, Charity Burbage, Alastor Moody, Rufus Scrimgeor, Gregorovitch, Bathilda Bagshot, Ted Tonks, Drik Creswell, Gornuk, Gellert Grindlewald, Dobby, Remus Lupin, Nymphadora Tonks, Fred Weasley, Colin Creevey, Severus Snape, and over 50 unknown and unnamed others.
Death Eaters and Allies: Gibbon, Peter Pettigrew, Vincent Crabbe, Bellatrix Lestrange, Lord Voldemort, and roughly 30 unknown and unnamed others.
For more information see: http://harrypotter.wikia.com/wiki/Second_Wizarding_War