Musicstrands has just released a beta of a recommendation tool for Mac.
As this is a beta I wasn't expecting a whole lot but I'm pretty impressed. The depth of catalog (based on other users' listening habits) isn't there right now so the recommendations aren't that hot, but I think that as it develops it will be a very interesting competitor for Last.fm.
The console is interesting. When asked to tag a song it gives a pull down list of different "buckets" such as:
* This song is good for:
* This song makes me feel:
* I heard this song in:
* This song reminds me of:
I'm sure as more users join, this will really help them create some great recommendations based on mood and locations and memories.
Last.fm still dominates though. It creates streaming radio stations based on the aggregated neighbor profiles and playlist comparisons. That reduces the barrier to entry and a very compelling service.