I like ABBA for the kids, lots to sing along with and very complex musically. We tend to play a very wide variety though.
One thing we tried for a while was giving each week (day) a theme, so 50's rock, classical, folk etc. That was fun and easy with things like Spotify.

Now the kids make their own requests. Number 1 Abba, number 2 The Ramones. (I'm blaming their father for that)