Cream - 'We're Going Wrong': the first Link is to the version which appeared on Tony Palmer's 'All My Loving' TV documentary in 1968. Very powerful!
http://www.youtube.com/watch?v=iyu2Fg6NIA8&feature=related

This second is a rather splendid version from Cream's Spaulding gig in May 1967, (Jimi Hendrix was also on the bill); I had never heard this or knew it had been bootlegged; amazing!
http://www.youtube.com/watch?v=k2Wb9LszeSA&feature=related