Cross-browser testing is one of those aspects of web development that no one really likes, but everyone has to do. It’s gotten better, don’t get me wrong. As browsers have slowly crawled (some more slowly than others *cough*IE*cough*) towards achieving standards compliance, the differences between browsers has become far less drastic than it used to be.
Multiple IEs
This is handy for when you need to test a website out in multiple versions of Internet Explorer. And its free! Windows only, but then again, IE for Mac is out of development, so its less of an issue. Installation is a breeze, and I’ve set it up on several systems without so much as a single glitch. No promises for Vista tho – I refuse to install it, so I can’t vouch for anything...
Firefox extensions I can't live without
The full list of Firefox extensions that I consider absolutely mandatory. All of these work with FF 2, and many work with older versions. All but one or two have also been updated to work with FF 3. (List last updated Aug 26, 2008.)