What browsers do you test your website in? You might be checking too many, or not enough.

Firefox is a no-brainer, as you should be developing in Firefox. It has the most options for developers and is generally the one that will render the webpage as the designer/developer intended.
Let’s move on to the others.
After Firefox, you should test the various Internet Explorer disasters builds. Leave IE6 as the last one, and that is up to you if you choose to support it. Many popular sites are no longer providing support for it, so you need to know your target audience and know if it is worth your time diagnosing bugs and issues in this browser.
A important tip, do not use the MultipleIE programs that package all versions of IE together. While we appreciate the work the developer is doing on them, we find that they do not render exactly how a standalone version of each browser displays. Unfortunately, the best way is to create numerious OS installs in Parallels, VMWare or some sort of virtualization software. Our developers tend to have 3-4 full OS installs of XP or Win7 for testing. One is not enough for proper testing.
After you are done with the big ones, test out Opera and Google Chrome. Once you test those you have hit the major website rendering engines. You can test Camino and Safari and others, but since there are only a handful of rendering engines, it’s not necessary to test a million browsers.