The Clash
The Clash-The Clash were part of the original Punk Rock explosion of 1976-77. Their sound added more Rock 'n' Roll elements to the 3-chord First-Wave Punk formula, and later added reggae influences. By their third album, in 1979, titled London Calling, they were barely still an "official" punk band- they had experimented with reggae, ska, rockabilly, and classic-rock-ish stuff. According to me, their first three albums (The Clash, Give 'Em Enough Rope, and London Calling) are all great, but where they forayed into Dub and Funk in 1980 is where I stop liking their music much. Combat Rock in 1982 (the one that spawned Should I Stay or Should I Go) is a disgrace.
Very few other bands have been known for their outspokenly liberal politics as The Clash (U2 comes to mind). This is the only other thing I can think of about them at the moment.
Link: London's Burning- The Clash Music Resource
MIDIs: As sorry as I am, Should I Stay or Should I Go.
Rock the Casbah- not as bad.