I'm evaluating moving from a dell laptop to a MacBook for work. I'm a mac use at home (desktops though) so I'm very comfortable in the OSX environment and would like to extend to work. One thing I do everyday, while my Dell is docked in my office, is route an external XM radio through the laptop's audio in jack. As I recall, I had to do some configuring to enable 'monitoring' or something when I first set things. This setup enables me to control volume/mute via keyboard shortcuts and play real-time through my regular PC speakers. I find the setup very convenient and don't want to lose the capability. I assume there is a way to pipe outside audio and listen to it real-time on the macbook but I'm hoping someone can confirm this.