First off, thank you to all you nesters for the great advice. Knowing that other people have gone through similar experiences helps -- we didn't realize how many of our family members had gone through this as well! We offered to split the difference with the sellers, and we're prepared to walk away if they won't come down. Our agent says we are "attractive buyers" because we are putting down 20% and we're ready to go, but we'll see.
The whole thing is a little dramatic, and now our broker (a friend) is warning us that our buyer's agent works for the same real estate firm as the selling agent. Our buyer's agent is also arguing that the appraisal is low, which my husband thinks is weird. I am going with the whole "if it's meant to be" thing right now. We don't have to move, and looking at this from a standpoint of perspective, this is not the end of the world.
We await their answer!
ETA: Just heard back, we are going to split the difference!
Re: update to low appraisal -- updated to add conclusion!
Edited by moderator.