I really do love the way you can tag pictures in Windows Live Photo Gallery. I find it incredibly useful to be able to tag the same picture with the tag "Cancun" and have it been automatically included when I look for the tag "Beach", "Trips" and "Fun Pic", since its a child tag of the former and also has a tag for the later. I also like that I can look for rating in the pics.
On the other side, tagging MP3 has always been a pain in the ass, because I just find it to hard to classify music! Is it pop? techno? techno-pop? rock? indie-rock? indie-post-classic-pop-techno?
I hate how ID3 just have one tag for genre, so I've tried tricks like putting all the genres I think it fits into, and then having lists in Winamp (which I dont use anymore) that filter out words in the ID3 tags (ie, Tag: Genre, Contains: Rock = rock list).
But then, what about moods? I want to be able to tag my songs in genres and in moods, you know, happy, concentrate/work, party, romantic (wink wink), etc.
Is there any way to do this, preferably in a way in which tags could carry on to other music players?