I generally consider myself a web developer. I work in ASP.NET, SharePoint, Content Management Server and the like. Been using AJAX features for years and have even done some Atlas stuff. So am I allowed to say that I don't use Firefox?
There's no real reason for it really. I'm just not dissatisfied enough with my IE experience to switch. Tabbed browsing to me seems like a serious step backwards. As I type this, I have six browser windows open along my taskbar. One for my gmail, one for my HSx account, two for an app I'm working on, etc, etc. I can tell all this because it says so right there on the task bar. If all of those websites are in various tabs, I lose all that and I have to go fishing for the window I want.
It's the same reason I rejoiced when Word stopped being an MDI (yes, it's still an MDI; you know what I mean). It's also why one of the first things I do to a new XP installation is to turn off “Group similar taskbar buttons” in my taskbar properties. And it's why I'll turn off tabbed browsing on IE 7 the minute I install it.
But back to Firefox. Like I said, I have nothing against the browser. I've tried it on and off since it came out (including version 1.0 PR which refuses to uninstall from my laptop). Last time, I think I remember it rendering things faster and I'm sure it does because everyone tells me it does. But IE's rendering time has never really struck me as being a problem. Then again, it's not something I generally pay attention to. Probably more accurate to say it's never been a problem I've noticed.
Some of the add-ins for Firefox look cool. I've tried a couple but didn't use them much after the initial love affair wore off. Same thing happens with portals for me. I try them for a bit, then stop when they don't fit in with my normal workflow. I use NewsGator to read my RSS feeds because I like that it integrates with Outlook. I can't get into opening a browser to do it. Just doesn't feel right to me.
In the end, I just don't care enough about browsers in general to make the switch. To me, it's just...well...a browser. For browsing. I don't care about the bells and whistles. I don't need it to aggregate my news. I don't need it to play music. I don't need it to remind me of the weather in Colorado every morning at 9:00. Yes, I build web apps and yes, I get excited about what you can do in a browser, especially with the likes of Atlas and Magic Ajax. I love the technology behind Flickr and del.icio.us. And I love building web apps that use it. Doesn't mean I use them myself.
Whenever I open my browser, it's to do something very specific. Run an app I'm building. Find a piece of code on Google Groups. Check out movie times. Do the crossword. These are atomic actions for me. I don't need to open a browser to some generic page and wait for the whole thing to load when all I want is one little corner of it. And I know I'm not the only one whose home page is about:blank.
So don't take this as a slight against Firefox or worse, as a vote for IE over Firefox. They're pretty much interchangeable for me. I use IE now because most of my clients want apps that target it. When more clients want Firefox apps, I'll switch. When Opera goes mainstream, I'll switch again. I just plain don't care as long as whatever browser I'm using doesn't get in my way.
What does interest me is that Firefox has spurred a nice little renaissance in browser development. At first I was kind of ticked that I had to go back to all my public websites and futz with them (don't whine to me about writing standards-compliant HTML; if IE's on 95% of computers, it is the standard). But now I'm pumped that some of these said standards might actually get supported. Especially the voice styles in CSS. Can't wait to build websites that talk to you.
But I'll never use one myself.