Hi Michael - that's right - just create each as a new site. As well as the geotargeting, it'll help if you can get a few links from each country to the relevant version of the site, as well as replacing the Dutch address in the footer with a UK and German address, if you have them.
As for .com or .com/nl, I prefer .com because it looks cleaner. Which would be most user-friendly? Personally I think if someone typed in www.headoverheels-fashion.com and it forwarded to www.headoverheels-fashion.com/nl, and they weren't from the Netherlands, they might be a bit confused. I'm not basing that on any science, it's just an inkling. They may think they can get to an English version of the site by removing the /nl?
