How many browsers do you test with? I’ve got five… and all on the same computer at the same time. Of course, we have Firefox, Opera, and Safari. Those are usually the easy ones to get right. But wait there’s two more.

You can install the beta of IE8 right now, but doing that takes IE7 off your system, right? Not unless you have IE Tab installed. IE Tab is a Firefox add-on that loads the IE ActiveX control inside of a Firefox tab. But not from IE8 that you just installed, it loads the IE7 control. Sure you can emulate IE7 inside of IE8, but you need to restart the browser to enable and disable emulation. With the IE Tab trick, you can develop web apps and have all five browsers up at the same time.

Of course, I’m not saying that you shouldn’t test on the same browsers in other platforms. This is just a great place to start.