The WyPiekacz plugin has a feature to template all your new blog posts with whatever code you want. Example, having the gallery shortcode in every new post so you don't have to type it or copy/paste it each time you make a new post. Just put all the other settings to something benign, 0 for most options and high for the max counts and leave everything else at default if you use it just for the post templating feature.
http://www.poradnik-webmastera.com/projekty/wypiekacz/