xPlayer is a free media player which I wanted to post for a long time, but waited until it was out of beta. Now I've been using xPlayer for a few months and I think its a great media player everyone should have in their Blackberry. Not only does it play the usual audio files but plays video files in full screen
FlipSide (BlackBerry) - Imagine seeing full color album art of your music and being able to use your trackball to swoosh to the album you want to play. Flipside does exactly this - and goes online to find the art you don't have..