Ipod Love

Yes, I realize that it's 2011...not 2001, but I just got my first Ipod!  In fact, a few weeks ago, this was me:

However, thanks to Patrick, I am now the proud owner of an Ipod Shuffle, and I love it!  I have only gone running with it once, but I seriously don't know how I ever exercised without it. 

Now I need your help!  The main reason I wanted an Ipod was for running, and I need more running approriate songs!  What songs are a MUST during your workouts?  Any help is greatly appreciated!