The place where you can get this feeling is surely the Sector Sci-Fi, the one that is dedicated to more classical Sci-fi themes. Where last year this area was a very high tech one, full of laserbeams and starships, this year the area is a small replica of the moon Pandora.
You can see home trees, forests where the blues and the purples are mixed with the greens, floating islands and of course a lot of Na'vi avatars (in the SL sense :) ) and skins.
The overall feeling is quite nice, even if I missed more classical SciFi themes here and there.
But it can always happen to see an Enterprise starship in front of a floating island :))