With Rightsizer, you can zoom text in specific parts of a web page, without affecting text in other parts. And once you set the font size just the way you like it for every part of the page you care about, you can have Rightsizer save those font sizes for the site. Then, the next time you visit a page on that site, if it’s got the same kinds of text elements, your preferred font sizes will be applied automatically.

You can also define a favorite font and size in Rightsizer’s settings, and have Rightsizer apply them where you want with one keystroke.

Requirements:
OS X 10.5.8 - 10.6
Safari 5.0.1 +
Universal Binary