I'd like to see more of Xandar, so props to it for making me desire more.
That being said, I still want to see more of how Asgard works, but we've had a pretty wealthy glimpse of it so far. Given that, it has my vote.
Speaking of all these civilizations, (pardon me for going off topic), but I still wonder where Asgard fits into the universe. What are the nine realms exactly? Are they just planets or are they separate galaxies or what? If they're planets, then the Bifrost seems pretty limited. Nine inhabited planets out of potentially millions? Big deal. And why are these planets so important that they have to be called "realms"?
In fact, the word realm makes me think of dimensions, so for the sake of the MCU, I'd prefer if they were explained as being at least galaxies apart, making the Bifrost somewhat like the Mass Effect Relays, which were responsible for helping even FTL ships get from one side of the universe to the other in reasonable time. Because ultimately the universe is so large that going faster than the speed of light isn't sufficient. Your alien grandmother's freshly baked cookies are going to be cold by the time you get there. That is, unless you bend space and time with either a rainbow bridge, or with the Tesseract.
Is Odin the All Father of the entire universe or just Asgard? Are the Nine Realms just his scope of authority and everything else is out of his jurisdiction?
Do the creative heads at Marvel Studios even know? Or are they just making things up as they go along and hoping things make sense in the end?
Why am I asking you all these questions? :P