Six months into Erin's pregnancy and all this stuff still applies to our search for a name. Thanks to those who left name suggestions in the comments. If anyone else has an idea, just leave a comment on this post. (Remember the criteria: known, but not common; easy to spell.)
And, no. We still have no idea whether it's a girl or a boy. Erin thinks it's a boy. I think Erin is a girl.
For fun, check this out. It's an interactive chart which allows you to track the popularity (in the US) of any name. It goes back to the 1880s.
(hint: my favourite boy name was the 17th most popular name in the 1970s; the girl name was 41st in the 1940s.)