As a backend Web developer (I do all that Geeky database and data-mining stuff in my day job), I'd be very pleased if everyone could just make do with Courier, ideally using a text-only browser like the venerable Linx. However, now thanks to openfontlibrary.org, you can easily jazz up your site. All the fonts here are available in font packs to support all modern browsers. If you combine this resource with the free FontPrep application (sadly available only for Mac) or a Web service such as everythingfonts.com or freefontconverter.com , you can even support older versions of IE.
FontPrep and everythingfonts.com will even generation the @font-face CSS for you. Then just reference your new custom font in your stylesheet by applying font-family: MyCustomFont, Helvetica, Ariel, sans-serif; either to the body tag or a specfic region or set of tags. It is that simple.
If you fancy creating your own font, you can download and install the free BirdFont app. This is available for Windows, Linux and Mac. It seems to import best from the newer OTF font types and let you import SVG files for individual glyphs.