Affordable home sound system

Hey. I'm looking for a new sound system and was looking for some input before I splash out.

For simplicity and portability (I'm a uni student so moving a floorstand speaker too/fro might be difficult), I was considering the Logitech PC speakers below. However I am mainly going to be using them for music and into heavy bass stuff, mainly dubstep and dnb. They may say they are 500 watt but are the small speakers going to create decent sound and bass? May be better off buying separate stuff but I don't own an amp and can't afford anything more than £300 so might not be able to afford that? Don't know a great deal about soundsystems. accessories~10725157

Any input would be great. What works well for you at home? Cheers.