I have to agree with the Godsmack tune, and pretty much anything by Sly and the Family Stone.
Also, Earth, Wind & Fire's Way of the World, and CCR's Lookin Out My Back Door, and Three Dog Night's Joy to the World (They're coming to Boston next month, and they still rock)! But I don't need to be feeling down to feel good when those songs come on, I just feel even better! Did I mention G&R's Welcome to the Jungle? My son's high school wrestling tune; very upbeat and exciting.