Well, the question only makes sense if you are speaking English or a close derivative. In other homo sapien languages you have other options...
Language Earth: Afrikaans arrde making us Aardvarks?
Albanian Toka making us Tokens?
Cebuano Yuta making us Yutans (not to be confused with Utah'ns)
Yoruba Aye making us all sailors?
Seriously, the most common word across all languages is Terra, since Terra is Latin and all romance languages have Terra as their word as well as some languages have adopted Terra directly into their language (like Yoruba) and since Terra is most commonly used in a science fiction context, when real aliens find us it won't be fictional anymore. Thus, an impelling case for Terrans over Earthlings, Earthers or apes-too-smart-for-their-own-good.
Given aliens would only encounter humans at this time or forward, I'd imagine they'd either call us (their name for our planet)-ings, or use the term from our dominant trade language which could potentially no longer be english in a couple hundred years (so earthlings, terrans, and even humans could be right out)
My question: What got you thinking about this Bercini?
This here is a very good example of someone (me) sticking his nose where he probably shouldn't because he can't add much and isn't really going anywhere himself either. I'll just go back to my home planet now. See you later blue-dotters.