Deep Purple?
 

What is considered deep purple's best cd?

machine head It contains their major mainstreme hit "smoke on the water"

i'd recommend 'Made in Japan' - it's probably one of the best live albums ever recorded :) and it includes Smoke on the Water also.

After "Machine Head" I'd vote "Perfect Strangers". awesome album featuring the reunion of the Classic Mark II line up. Unfortunatly it was all downhill from there.