Permanently change default post author

I recently linked multiple blogs under one WordPress account. Now that account’s username is my default administrator and post author. Its username is irrelevant to this blog and I don’t want to use it.

When using the WP interface, I don’t want to change the author each time.

It would be really helpful if you could offer a simple way to set the default author in the ‘Writing’ settings so we can set it once and forget it.