This question will be submitted as a wiki. The intent is to gather valuable configurations, deployment ideas, and smb.conf settings to assist with this wonderful service.
Having used this for over a year in a mission-critical role, I can safely say that there are ups and downs to using this software; but along the way, I also learned a thing or two that separates truth from hype. What things have you encountered, done, or otherwise thought of to make this service work its best?
Follow-up:
I've taken to posting answers to my own question, as no-one seems to have an "incentive" to provide their own answers. Even though it's a community wiki I would rather refrain from answering my own questions, if possible, so if you have something to share, please please please leave an answer!