Soulseek v151 - now with recommendations. Make a list of 'Things You Like' and it should provide recommendations of new music and similar users.
Later... Now that I've tried the recommendations feature, I'm pleased to say it works a lot like HeadCloud. You're not limited to bands or albums but can enter anything you want into the 'Things I Like' box. Press a button and your favourites are compared to everybody else's, returning a list of the users that have the most similar tastes to yours. Plus, a list of recommended bands is calculated - I already discovered Explosions In The Sky in just this way. That should be a good enough reason to download the client and give it a try, even if you're not interested in sharing any of your own (or any other freely-licensed) files.