Terra, it's Latin name, may be the best we can manage in the Latin alphabet. It's the root of the word "terrestrial" (our ecology) and "terran" (ourselves, among other species). It isn't quite as religiously suggestive as "Gaia" and it isn't as astronomical as "Sol-3". The Greek word "planet" is itself problematic, meaning "wanderer" and implying that ours is merely one among many, denying the uniqueness it holds for us. For all these reasons, the best word may simply be that for "home".
What are the consequences of thinking of Earth, or Terra, as merely the third of a set of eight or nine planets, as merely a wanderer in space, true as that may be from the limited perspective of physical astronomy? I submit they're not effective for our actual intention, which is to align our world so well with the biosphere it lives within, that eventually we perceive ourselves as having zero "footprint" on it, living in a "sustainable" way that eventually restores it to its original state.
For those who share this vision, the name "Gaia" is too safe, it implies that somehow the biosphere will itself perform this task, that no matter what we do, we'll be restored to equilibrium. The name "Eden", likewise, implies a desire to return to a state of innocence, but perhaps this time as the caretaker who has eaten of the apple and knows how hard it is to maintain. But if we go back, we must be sure that we go back as stewards, not as owners, not as pets, not as the creator.
Either of these words may be too loaded with the child-like innocence and leaving the cleanup to others. This may be even more dangerous than the belief that we're merely the third of eight wanderers, or only one client of one of many stars. There is no evidence whatsoever that we could ever reach other habitable rocks in space, and even less that a species that destroyed or fouled its home could expect any welcome other than to be blasted out of the sky as soon as they appear. There is no room in a wise civilization for a locust species that considers itself so superior as to burn out planet after planet, cause extinction after extinction, and depart sad but confident with "lessons learned". No doubt any other intelligent species is quite sensitive to the potential harm done by such visitors - look at our own science fiction and horror stories. We spend a lot of time warning about this kind of alien ourselves, and that despite the fact that we merely suspect they may exist.
When we travel, or send messages, we should be no less aware. For all we know, implications of the name we give our homeworld ("dumping ground", "crash pad", "third of eight", "somewhere to stand until we can blast off again", "somewhere that takes care of us while we take no responsibility", "what we own") may be all that matters to alien observers. Maybe they look at the Arecibo message and ask "where are the other species? why is there only a picture of one man there? why is it a man not a woman? why is mathematics and chemistry important but not ethics or spirit?" Maybe there are very good reasons they do not talk to us.
Whatever the name we choose, we should choose it carefully. For it must be part of any message we send into space, any signal of peace we send, any identity we form in common with other species on our world, including possible future intelligent species - those we might create, those we might become, those who might arrive or who might have been here all along. What we call our world says it all about us, and it would be fair, right, and proper for us to be judged based on that alone.
A final proposal: Any agreement among us must include (in "us") at least all those species who are capable of communicating with humanity, including at least the few gorillas, chimpanzees, orang-utans and bonobos who have learned some sign language. If we found a single symbol and sound that all could utter and agree on, then, we'd be able to say at least one thing that would reduce the chance of alarming, angering or abusing those we approach.
That is, we could say, "we agreed...", and "we" would include at least not just the humans who sent the message, but at least some of those who share our home and our genetic heritage. Anything less would send a message that we don't care, disrespect, even deliberately attack and extinct those who are even slightly weaker or different from us. And could there be any more dangerous message to send out to space for all to see?
Maybe the locusts wait. Maybe they wait for signals of single-species arrogance, an indication of rivalry, of challenge. Maybe they look for species that destroy their own close relatives, since there is no chance that any other would come to their aid.
Maybe the name we choose for our world is the single most important signal - to them.
Choose wisely. And keep watching the skies.