Rivet - always thought that it was weird that a band could take a Sonics track and make it heavier and rawer. Their version of It's Not Easy (Rolling Stones) also very good.
How about (very obvious) Flying Lizards version of Money? Loads in that post-punk vein, Slits version of Heard it Through the Grapevine (though maybe not actually better than the original - which was by Martha Reeves I guess so you could in fact say Marvin Gaye's version surpasses the original), Devo's take on Satisfaction etc etc