Thanks for the responses, but as I said, I've been to Copenhagen before quite a few times (done Tivoli, Nyhavn, Christiania, Mermaid etc), and am just looking for something near the airport within walking distance. I was looking for a nice beach or park, nothing touristy especially. I'll be back in early September for the day, when I will go into the city for the day.

That being said, everyone keeps saying "go into the centre", so i'll pose another question. Wikitravel says it's 36 kr for a 3 zone ticket that will get me into the centre. It's valid for 75 minutes....can I use that as a return ticket if I only want to stay in the city for an hour?