I would have to say mine was NSYNC. I had posters of them covering 3 walls of my room and then the other wall had various bands, mostly latin singers that I grew up listening too and still listen to today.
I wasn't really allowed to listen to pop or rock music as a child. But, when I was a teen, I started buying my own music and found that I liked rock and metal. My favorite band was Metallica and my favorite singer was Alice Cooper. He's not the best singer in the world, but he puts on one heck of a good show. Since then, my musical tastes have changed some, but I still like listening to Metallica.