Q: In a rock band what could be better than hearing the drummer banging out a killer rhythm?
A: How about two drummers?
Most popular with groups formed in the seventies, the phenomenon of bands with two drummers -- each with their own full drum kits set up live and/or in recording sessions -- have included the Allman Brothers with drummers Jai Johany Johansen & Butch Trucks, the Doobie Brothers, the Grateful Dead with Mickey Hart & Bill Kruetzman, .38 Special, the Outlaws, Genesis (post Peter Gabriel as in the above clip from 1976 with dual percussionists Bill Buford and a bearded/pre vocal pop sensation Phil Collins), (for part of their career) space rockers Hawkwind, King Crimson (in the nineties), Foreigner, Yes, Adam & the Ants, and the more contemporary rock group Modest Mouse. Note that some of these only occasionally/sporadically utilize the two drummer set up.
The advantage of having two drummers varies depending on who you ask. In fact, many believe that it is just plain unnecessary -- that if one drummer is good enough, that he/she can do an adequate job alone. There are many reasons to utilize two drummers, including that together two drummers can create a more full big beat sound and groove, that they can switch up types of drums each play, and that together they can really speed up the tempo.