These fonts all look the same

I believe, Jak, these are the characters Firefox supposedly shows for certain undefined characters, but that it doesn’t recognize that the fonts concerned actually have them there. There have always been some major issues with Firefox typography, and while many of the serious ones have been ironed out, it looks like this one hasn’t.

Jak, I think you are right. It must be the engines, and ironically, IE is the one that renders many of these characters correctly. (I have not used it on this particular page, but when I went from IE7 to Firefox 3, I noticed these boxed characters with the hexadecimal codes appearing everywhere.)
Being a font guy, I am often concerned about the compatibility of a lot of our fonts. That would be the number-one reason to not adopt Linux on my part, especially having licensed thousands of PostScript fonts over the last 20-odd years.

As you may have read, Jak, I had sent information to the Mozilla people about the Firefox typographic problems (the failure for the Gecko engine to render even quotation marks in the correct font) and this remained faulty for versions 1 and 2. Version 3 is far superior, fixing some of these, and introduced recognition of kerning pairs (the space adjustment between two characters). So I agree, the open source community should have accepted and remedied some of these faults, especially when they were so glaring. But it took three years.
I was a huge supporter of the original Netscape browser, right up to version 4·7. It was only out of necessity I switched to IE5, which at that time was a fairly good browser, and the best for typography. (Netscape stopped recognizing PostScript typefaces, then still current, with version 6, at least on Windows.)
I also agree that Internet Explorer is an inferior browser in many respects, from standards to its sheer size. Even on a brisk Vista machine which I now have, it’s a clunker. It’s many, many times worse on the two XP machines in this particular office.
I haven’t checked Opera yet. I have checked out Chrome (downloaded within the first 24 hours!), Maxthon (IE engine, but its own skins, and much faster than IE, but slower than Firefox or Chrome), and, of course, Firefox. I have found quite a few errors with Firefox, sadly, especially with Wordpress, but they seem to have disappeared with the latest (2·8) incarnation.