I'm generally not a big fan of live albums but, in this group's case, I'll make an exception:
Earth, Wind & Fire - Greatest Hits Live
One of the most influential (and eminently listenable) groups of the seventies, and this is a live performance of their best hits: September, Shining Star, Let's Groove, Boogie Wonderland, Reasons, After the Love is Gone... Solid Gold, from start to finish.