"The Hard Part is Actually Changing Your Mind" is the absolute worst from that list. It tells someone absolutely nothing -- hard part of what? Changing your mind because of what? It's not even clear what the topic of the book would be. Could be a political memior, for all I know.
I like a variant on Dahlen's suggestion: Methods of Rationality: A Less Wrong Guide to Beliefs, Biases and Bayesianism.
"... to Beliefs, Biases, and Bayes" is shorter and snappier.
Quantum Computing Since Democritus got me thinking that we may want a more riveting title for The Sequences, 2006-2009 ebook we're preparing for release (like the FtIE ebook). Maybe it could be something like [Really Catchy Title]: The Less Wrong Sequences, 2006-2009.
The reason for "2006–2009" is that Highly Advanced Epistemology 101 for Beginners will be its own ebook, and future Yudkowskian LW sequences (if there are any) won't be included either.
Example options: