What, is that a wind-up? I love German music, whenever I dj it's quite common for me to realise afterwards that half of the stuff I played was German.I like that they go quite hard. Good quality beer and drugs as well. Terrible music generally speaking, as well as terrible taste, but it's swings and roundabouts.
Cologne and Dusseldorf are really near each other so if you do it right you can get the best of both of them - Cologne has the cathedral and record shops, loads of hipster cafes and so on whereas in Dusseldorf you've got amazing museums centred around the art academy. And obviously you've got this krautrock, post-punk, techno embedded in the dna cos of Kraftwerk, Neu!, Malaria, DAF, Liason Dangerouses, Mice on Mars, Kriedler, Lena Willikens, Can, Gas, Kompakt, Floh de Cologne... and some very good restaurants I find.
Hamburg is supposed to be good too but I've never been.