What's a good Android app for keeping my music organized while I'm showing properties and don't have Wi-Fi?

As a realtor, I'm always on the go, and sometimes that means showing properties in areas with spotty cell service. Music Player Offline & MP3 has been a lifesaver for keeping my music organized. I can create different playlists for different moods – something upbeat for open houses, or something more mellow when I'm driving clients around. It's important to me that my presentation is polished, and having my music ready to go, without relying on a data connection, really adds to that. Plus, it's just nice to have my favorite tunes available when I'm between appointments. It helps me stay relaxed and focused. The interface is clean and client-friendly, which is always a plus!