Songbird includes code base from Firefox and is very familiar for Firefox users when adding add-ons and themes. I am running Songbird on OS X and Kubuntu 7.04 and plan to install on an old WIndows XP machine I have sitting in the corner, but so far it seems very stable on Mac and Linux. 

I have seen install help on the internet for Linux and my suggestion is to not place in the /opt directory, but rather unzip to home and fire it up from there - you do not need to install. I created a link to the executable that can be found in the unzipped Songbird directory.

The down side to this great player is that is is very beta and not totally solid yet. Even though I haven't had any problems you may, but I would seriously keep this application in mind, because it seems pretty solid where it shouldn't be long before most issues go away.  Also, some features are not working yet. The cd burn and cd play do not work yet.

Eitherway, I love this application so far and plan to keep using it on all my machines. My wife has an iPod and iTunes wouldn't play some internet radio feeds that Songbird will so she has switched. Not sure how good the iPod support is as she hasn't used that feature yet but I haven't seen many posts on the subject so I am guessing it is pretty good.

Visit here for a list of features and screen shots.

Here's a screen of my Kubuntu box running Songbird. Warning: Full image is 1440pxx900px!