Honestly, I think that Last.fm is one of the best web portal ever done, on the design side I mean. My appreciation comes partly from some little clever intuitions (e.g. the avatar-button), partly because of its graphic consistency, which never slips into visual bore.
Now I’m wondering if the new Facebook like button, which is spreading webwide pretty fast, will replace the “native “rating” system or if Last.fm’s guys will stuck to the orginal design.