I've gotten far too used to Postgres' ability to authenticate you by your system uid, and tire of the continual copy-paste of massive passwords for my MySQL servers.

However, there is a way to streamline this: create a .my.cnf file in your home that looks like:

[client]
user=myname
password=mypassword

Just make sure that you are the only one who can read it (chmod go= .my.cnf), and you are good to go!