The '70s and '80s rule as two of the most popular bands from that era join forces on Chicago/Earth Wind Fire - Live at the Greek Theatre, a two-disc, nearly three-hour concert recorded in Los Angeles in 2004. These groups scored dozens of hits in their heydays, and if neither has come up with much of anything that's new in the past two decades, the sold-out audience at the Greek Theatre could hardly care less. Both Chicago and Earth, Wind Fire, have soldiered on despite key personnel changes over the years (Chicago bassist-singer Peter Cetera and EWF founder Maurice White are long gone, and much missed); here they perform energetic and tasteful versions of everything from "Make Me Smile," "I'm a Man," and "Saturday in the Park" (Chicago) to "That's the Way of the World," "Fantasy," and "Serpentine Fire" (EWF), among many others, to rapturous response. Nothing too exciting about all of that--in fact, it's a bit like witnessing a couple of very skilled tribute bands at work--but there are a few surprises, as when Chicago keyboardist-singer Bill Champlin takes the lead on "After the Love Has Gone" (which he co-wrote) and EWF singer Philip Bailey returns the favor on Chicago's "If You Leave Me Now." The highlights are the first and last portions of the show, when the two bands (complete with horn sections) share the stage for "September," "25 or 6 to 4," "Shining Star," and more, displaying genuine joy at performing together and generating a huge, infectious sound delivered with high definition visuals and digital audio.