Lets say I have a few objects that together form a nice layout for a room. I can select all of these objects and move them at once. But what if I want to put them all somewhere else, in another worldspace? Is it possible to do that, say by moving them or copying and pasting them?

Yes, simply highlight all the objects you want moved/copied, and hit ctrl+c then move to the worldspace, to the generic area you want them and hit ctrl+v and they should all appear there. They will all automatically be highlighted still, so just click and drag them all at once to where you want them, and presto a perfect copy of your previous area.

Oh, thanks!

Locked per OP request.