For dubstep and hiphop you're probably going to want a subwoofer. Otherwise you're going to end up turning the speakers up past their limits and damaging the speakers. I've seen it done before. If it's just for personal listening, I would recommend headphones before recommending those for full range listening. And you definitely need to get two.
Mono sound is so 1880.
If you want to continue with looking at speakers, I'm going to suggest the Klipsch Promedia 2.1. They're not the most accurate speakers, but they're definitely fun to listen to and easy to set up.