As some of you may already know, Firefox reached 1.0 today. I think I have some words to spend on this. I'll try to spell less about Microsoft.
If you're old enough to remember Microsoft's inclusion of Internet Explorer to Windows 98 followed by the reaction of Netscape; you'd remember how Microsoft killed it on Windows. Though it was able to survive on Unix-like deployments, Netscape lost the market. That's what happened.
To be able to fully replace Netscape Communicator Suite (browser, mailer, newsgroups-reader, full-featured HTML composer and such), Microsoft had to invent Outlook Express and Frontpage Express. You're right, they were stripped-down versions of the same names. And yes, you were getting them for free with your copy of Windows. (I didn't say they were good or bad or anything, I just tell you they were there even if you have installed nothing along with your Windows.)
By the way, I never liked Opera at all. Not that it's based on the legendary Qt widget set, it merely sucks in the usability area. Here is the rule: showing-off every single feature the software has doesn't make it any better. It goes very well along with KDE and Gentoo, if you like espresso with sugar and cream. (No flames, I'm just being honest.)