The number of new audio formats keeps increasing as people find ways to compress music into ever smaller files while maintaining sound quality. Cog is a simple audio player that makes sure you can play all of them.
The problem with changing formats is that your audio player - such as iTunes - soon gets left behind until updates are made or plug-ins developed. Cog is designed to solve this problem by offering compatibility with just about any format out there, including the more obscure ones. These include Ogg Vorbis, FLAC, Musepack, Monkeys Audio, AAC, skip and Wavpack.
Cog allows you to drag and drop files into it, read unicode tags and create playlists. What's great is that Cog supports Growl alerts, so you can see what's playing without even looking at the player and it can even scrobble what you're listening to to Last.fm. It's completely free to use and open source so you can modify it as you like.
The preferences are very limited and there's no album info, cover art or artist info included in it. There have also been some playlist corruption problems in Snow Leopard, although these are set to be ironed out in the next release.
For anyone that needs a free but powerful audio player for all but the most obscure formats, Cog is a great solution lightweight solution.