My wife and I both wanted something creative and atypical but not totally off the wall. She always liked the middle name Josephine, and I always liked the name Rosetta (part because it sounds cool, and part because of the awesome post-metal band from Philly). Then one day we stuck them together and realized:
"We can call her Rosie Josie!"
DONE.
We have one more set of boy/girl names picked out - we want to adopt a girl, but I don't know that we'll ever have another biological child. (But the boy's middle name would be Auron.)