I personally think they are all cool in their own way. Onew is cool because he cares so much for his members and that he makes people laugh. Jonghyun is cool because he isn't afraid of being his true self and that he mainly speaks his mind not caring what people think. Key is cool because of his style and that he is the member who tries out new things first like shaving his hair. Minho is cool because of his calmness and being the face of SHINee. He is also very athletic. Taemin is cool because he is very talented and isn't afraid to mostra people that he can dance and that he doesn't mind having long hair.