Second city from Amsterdam for 10 day total Euro Vacation??

I’ll be in Amsterdam for five days in late September. I’d like to travel to another city via either a direct flight or train. Any suggestions? Given I’m from the US, a non-Euro currency country would be preferable (I’d love to do London or Paris again, but they’re too expensive). I’ve seen a great deal of Europe (toured Italy, Spain, Germany and parts of Eastern Europe extensively), so a slightly more obscure location would be great. Thanks.

The closest non-Euro currency country to Amsterdam after Britain is Denmark.
Capital Copenhagen.
Great city. You can have a realy nice time there.

Scenic Tours – Eastern Europe 2011