I think it depends on your target audience. If your website is written in Dutch and only targets people who live in The Netherlands, then by all means, you'll get better overall results with the .nl extension.
cscgal
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I think it would be fine to have the exact same website but an .nl version written in Dutch and a .com version written in English.
It doesn't count as duplicate content if they're in different languages. The duplicate content penalty only applies to a direct copy/paste of a large portion of text.
cscgal
The Queen of DaniWeb
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