This is a handy trick.
I had installed Jeena Paredies’ TextEd.app replacement for the default TextEdit app because there was no way in the preferences to open with a blank file by default.
The only problem with this is that the Mac would never remember setting TextEd to be the default app for .txt files often leaving me with both apps open.
I then found this thread showing how to disable the file picker when launching TextEdit using the following command:
defaults write -g NSShowAppCentricOpenPanelInsteadOfUntitledFile -bool false
And now I’m back to just one plain text editor again.