What is the most efficient method to store a Python dictionary on the disk? The only methods I know of right now are plain-text and the pickle module.
Edit: Sorry for not being very clear. By efficient I meant fastest execution speed. The dictionary will contain mutable objects that will hold information to be parsed and modified.
JSON and YAML work well, also.  
Depends on what you mean by "efficient"?  Size of file?  Time required?  Amount of code you need to write?
You have the timeit module available to determine what meets your specific criteria for "efficient".
Efficient method to store Python dictionary on disk?