Wikipedia includes a picture of all three: https://upload.wikimedia.org/wikipedia/commons/8/85/IMac_G4_Generations.jpg https://upload.wikimedia.org/wikipedia/c

Wikipedia includes a picture of all three: https://upload.wikimedia.org/wikipedia/commons/8/85/IMac_G4_Generations.jpg https://upload.wikimedia.org/wikipedia/commons/8/85/IMac_G4_... The 20" definitely looks the least balanced (aesthetically).