An easy answer: My favourite Kraftwerk-CD hasn't been manufactured yet.

I don't like their music, their sound and their "lyrics"/"vocals". Or, in a shorter form: I don't like Kraftwerk.
!!!!I'm not talking about the persons themselves, only about the band/ the music!!!!
I can't understand why they are so popular. Only because they were the first, the synth-pop pioneers? Maybe I have to be a little bit more patriotic and have to like them because they come from the same country like me. But that would be very silly, I think.
They've never had a good sound, and their "melodies" a new born child could have composed and played. Music doesn't need to be complex and perfect. It "just" needs something special, something that makes me like it. But Kraftwerks music has nothing special.

"Radioactivity is in the air for You and me" or "Fahr'n, fahr'n, fahr'n auf der Autobahn" are not really masterpieces of lyrics, are they?

I don't say that everything from Kraftwerk is bad, there surely are some usable elements. But the complete end-product of a Kraftwerk-song is nothing really good, I think.

EVERYTHING WRITTEN HERE IS JUST MY PERSONAL OPINION!!!!!!