Further investigation -- we always do that *after we post*, right? :-) -- suggests it might have been a corrupted internal table. I flushed Now Playing, and then re-added my entire 900 track list, and now it's behaving better. Not as well as on 2007, but still better.

I couldn't play *anything* from the library directly, though.

Anyone got any better suggestions for a music player suitable for car-rack-mount use? I need play/pause, skip, and preferably track-repeat (I commit karaoke pretty regularly; that's how I learn songs) as Big Buttons, and really tight UI response.