Yes, dubstep originated in UK. Thus, this makes it a good localized/geo domain for dubstep from UK. There are definitely some people who'd be interested in buying this domain name, but once again, the same with dubstepblog.com, the domain initially has no value, but it has lots of potential and that is what you can sell.
You can build a solid fanbase if you feature UK artists. The dubstep genre has been reaching a point where there's actually different styles of UK originating from different countries. Therefore, it's a good time to create this.
I'd appraise this at $xx to early $xxx, but only if you can sell it to relevant blogs and or music enthusiasts. You can also go for a directory angle.