This program doesn't take up a lot of memory and is very stable. It's especially useful for playing single songs, but it's also able to play playlists or folders of audio files. You can also use it online or with audio CDs.
Also, Trout has interesting features like customizable keyboard shortcuts, an album art search button, notifications for when the song changes, and its ability of being combined with Last.fm.
With all these features, Trout is a pretty attractive alternative to the more popular music players that exist nowadays.