I'm writing a Python script that is only meant to be run from the console. e.g.: $> myscript.
I'm wondering what is the leading conventions in Python for scripts of this sort. Should I call it myscript, or myscript.py?
Yes
Why? 
Portability
Python scripts in Linux environments are recognized as such, but NT is... special. If there's ever a need to move it to anything made by microsoft, you need the extension. 
Readability
Appending a filename extension to it will make it obvious what kind of file it is, for when others look in your directories. 
Useability
If ever you need to call it into python as a module, you NEED the .py extension.
Convention
It is the standard for all python scripts to have the .py or .pyc extension on them.
Should executable Python script be named with .py?