a musical question-

most rock bands have a similar line up- singer, one or two guitarists, bass player, drums.  some add keyboards, sax or even a second drummer.  but usually those are the roles in the bands.

it's always more interesting when there is more than one lead singer within the group.  I can think of a few that ALL the members sing songs-

• the Beatles
• Kiss
• the Bangles
• the Eagles
• the Runaways  

and a few that have/had at least two singers-

• the Romantics
• Night Ranger
• the Cars
• the Who

can anyone else think of bands with two or more vocalists that consistently shared duties?  this doesn't count purely vocal groups, of course.