Is there any good system for Android to let you catalog your music, create playlists, and copy it to your device? Bonus points if it can let you reject/delete music and have it reflected in the UI on the device?

Kies bites. It's just awful. It doesn't show metadata properly, and it's horrible at creating playlists.

I've discovered playing music from the phone is far far far more battery efficient than streaming Pandora, so I'd better get some music on there in a way that's easy to play.