OK I just read your itinerary and will comment on the cities I stayed in.
Copenhagen, Denmark: I stayed at a Hosteling International Hostel on the outskirts of Copenhagen that took like a 20-30 minute bus ride to get into the main part of the city. (
http://www.danhostel.dk/vandrerhjem....=uk&id=144 ) I think this is the same company, but their location seems to have moved to a better location. Their facilities were clean and the staff was good there from what I remember.
I walked around this city a lot and took pictures. If you are into museums at all the National Danish Museum was pretty good. I don't have a calendar out but if you can avoid being in Copenhagen on Monday you will have a much better time. A lot of the touristy things to do are closed on Mondays. At least at the time of year I was there (late September)
I don't know if you are into graffiti at all, but if you are you should definitely try to check out the rebel town Christiana. (
http://en.wikipedia.org/wiki/Freetown_Christiania ) Its a hippie town that has like 800 residents and it had the best graffiti art I've ever seen. (A couple pics are on my website
http://www.kipin.net )
I know there was some talk of the Danish government shutting Christiana down when I was there 1.5 years ago so perhaps it no longer exists but its worth looking at if you are trying to kill a few hours. Also, hash is really easy to score if you are into that thing (The dealers all stand outside on "Pusher Street" and offer it to you - I declined [img]/images/graemlins/smile.gif[/img] )
Berlin, Germany: One of the best parts of my last trip was taking a free walking tour sponsored by this group (
http://www.newberlintours.com/nbt/ ) It was awesome and the guide was very knowledgeable about everything. All the guides are also native English speakers but they also speak German so it is pretty cool.
If you have the chance to do this, it is definitely worth checking out. I also went on their pub crawl and had a lot of fun. You get good discounts on drinks at bars and get to meet a ton of travelers.
I havn't been anywhere else on your list besides Paris and I don't really feel all that confident giving advice on Paris.