I was never a huge fan of The Clash, possibly because the early-teen nightclub I went to in the 80's (named after a Bowie song but presumably referencing it's just-pubescent clientele, it was called, uh, Changes) played Should I Stay Or Should I Go all the time. It's a shit song to begin with, but, with it's excelerating tempos, it has no place on the dance floor.
However, my two favorite covers of the moment are both Clash songs, and I'm actually looking fwd to seeing the new Joe Strummer doc. The first is Clampdown, by The National, who slow it down, strip it down and remove the twitchy riff. The second is a series of versions of the Guns of Brixton. The most recent is by Santogold and Diplo (who played Mercer Union's New Years Eve party a few years ago). It's available here, but probably only for a while. They've renamed it Guns of Brooklyn. The others are by Arcade Fire (decent, but bad sound quality, a live recording), Nouvelle Vague (surprisingly okay, from the first album, before the novelty wore off) and Calexico (not overly inspired, but competent as one would expect from the band).