Just purchased this: http://www.amazon.com/gp/product/B00..._detailpages00 based on some recommendations and reading in this and a few other threads.
I'll post again once I get it up and running (might be a few weeks).
ETA: I also bought one of these, which should keep it running for about an hour and 20 minutes if the power gets interrupted: http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER