I love Google Reader for reading blogs, but one thing that bugs me is the rather dull choice of font: sans-serif (Arial if you're on Windows). If you have Vista or Office 2007 installed then you have a much better choice of fonts, one of my favourites being Calibri. If you don't have Calibri, Microsoft 's trusty Verdana font is more readable online. Unfortunately, there's currently no way to change the font in Reader's settings pages. But, if you're using Mozilla Firefox you can take advantage of user CSS and style any website however you choose, as long as you understand CSS.

Firefox's user CSS lives in a file called userContent.css in the chrome directory within your Firefox profile which on Windows is somewhere like: %APPDATA%\Mozilla\Firefox\Profiles\<some alphanumeric id>.default\chrome\userContent.css.

Create the userContent.css file if it isn't there already (there will just be a couple of example files there initially) and add the following:

@-moz-document url-prefix(http://www.google.com/reader/)
        font-family:Calibri !important;
        font-size:105% !important;

Tweak the font and size to taste.

Internet Explorer also allows user stylesheets, but there's no ability to target certain styles for specific sites. It's made possible in Firefox by the "@-moz-document" and "url-prefix" psuedo-selectors.

It turns out there's quite a community with the same idea: that they can tweak sites to their own tastes. So check out http://userstyles.org/ and the Stylish extension, which makes it even easier to apply user CSS, and a huge repository of ready-prepared CSS for popular sites, which you can use if you're not CSS-literate. Daniel Cazzulino has a great example of a pimped-out GMail courtesy of Stylish.