Cross browser support is important for your website. It's a general usability issue; users should be able to access your content and should not be forced to use a particular web browser or technology to view your site. Adding to this your site should render consistently especially considering all the different web browsers options available now.

Using Cufon
Dealing with web typography can be a disaster. Finding a font that fits the site, setting the font-family CSS property (and "fallback option/s"), then testing the rendering in different browsers.