I really enjoy the evening music: 5 PM, 6 PM, 7 PM... Holiday music is the best, though: Halloween, Toy Day, Bunny Day!! I'm really looking forward to Halloween.
8pm is my favorite! It feels the most ACNL-ish to me, since the beginning of the song is the ACNL theme.
This isn't part of the question, but I thought I'd add that I really don't like 7pm or 1am that much... So many people seem to like them, but both of them make me sort of sad and creeped out. I don't know why either! The rain and snow versions are easier for me to listen to, I think.
Toy Day music! It feels so magical, and it sounds just like a little kid's feelings on Christmas morning: nervous, excited and, the most important, feeling the magic of Christmas.