Nusic.fm has all of the features you would expect given the title of this post, as well as a stack that allows you to play tracks from Youtube and Soundcloud (more services coming soon) whilst still browsing the site for other content. The cool thing about this is that to the user it appears platform agnostic - using the stack with any media source seems exactly the same. No more following links to different sites to play media and comment on things, it all happens on one site, seamlessly.
The site also allows 'combined charts' (think merged subreddits), so if you are interested in 2 (or more) genres you can make a personalised chart showing both at once, with ease.
Naturally, we have last.fm scrobbling integration and lots of other nice little features, thanks for taking the time to read this and we hope you like the service! Feedback (good or bad) would be greatly appreciated.
Sam and India (Nusic.fm, UK)

Why is it better than hypemachine?
Hi, thanks for the reply.
We believe Nusic.fm is better than Hypemachine because it is a truly social experience, as Hypemachine just crawls for songs from other blogs. We allow anyone to upload a track and for others to rate it in a truly crowd sourced way. In practice this means that if an artist submits to our site and other people like it, it gets the respect that it deserves. But if that same artist wanted to get onto Hypemachine they would first have to charm a blogger that Hypemachine has hand selected.
Hypemachine also lacks a number of features present at Nusic.fm. For example, combined charts that reflect the fact that music rarely fits only one genre.
I hope this helps clear that up.
Thanks for the detailed explanation! I will give it a deeper try then.