Music is a terrible choice for a voting system. The homogeny of opinion for sites like Hacker News or even Digg is way higher than any sector of music listeners, and it's this homogeny that aggregators depend upon to remain useful. To put it another way: without curators, you need to all think alike.

The only way I can see this site working is for rankings to be calculated on a per-user basis, based upon the votes accrued from the user's neighbours. This would go some way towards the mental filter I use for music recommendations from friends: do I trust this person's music taste?