Change your Readability bookmarklet URL to the one below and you'll get styling similar to John Holdun's Re-Reader.
Replace http://dl.dropbox.com/u/166030/readability/readability.css
with whatever, if you want to make changes.
For some reason serving it raw from Gist doesn't work, so you'll have to host it. Dropbox is pretty good!
javascript:(function(){%20readStyle='style-rereader';%20readSize='size-rereader';%20readMargin='margin-rereader';%20_readability_script=document.createElement('SCRIPT');%20_readability_script.type='text/javascript';%20_readability_script.src='http://lab.arc90.com/experiments/readability/js/readability.js?x='+(Math.random());%20document.getElementsByTagName('head')[0].appendChild(_readability_script);%20_readability_css=document.createElement('LINK');%20_readability_css.rel='stylesheet';%20_readability_css.href='http://dl.dropbox.com/u/166030/readability/readability.css';%20_r