Pop-punk never went in for flashy theatrics—until these Vegas showmen burst onto the scene in 2005. Panic! unleash dramatic impulses that land somewhere between a punk rock club and a vaudeville show. The band fold accordions, organs, synths, dance beats and Brendon Urie's quivering howls into a spiky mix of guitar pop, sealing it all with song titles that could serve as snappy haikus. Aside from Urie's commanding presence, the lineup has been in a constant state of flux, which has only spurred forays into Sgt. Pepper-esque pop, electro-rock and even a little hip-hop.