One thing that prevents me from using common fonts like Tahoma or Century Gothic is the fact that I don’t know how many people have that font installed on their computer. Here’s an excellent article giving both the list of fonts and how many people have it on their PCs/Macs. For Linux, there’s also this list.
Here’s Eric Meyer’s discovery on the issue. The intrinsic value of “normal” for different font faces on different browsers, it turns out, is totally wacky. The moral of the story is to simply avoid using it for any precision, cross-browsers compatible work. Which is all the time, I should say.
This is a happy day to be a Opera user. Still in alpha stage, Opera Dragonfly is a promising tools similar to Firebug or Web Developer Add-on, both for Firefox. By the way, here’s an entire Opera Widget section dedicated to Web Developer category.
This is one of those articles that, upon its existence, will spark a new trend on web visual design. So go read it.