Feel free to not use it.
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It looks a lot nicer too. At least on Win7.
Firefox is a true libertarian browser as it gives freedom in adding to browser features that ultimate user, not developer, wants. Sure, it has its disadvantages: big memory usage, windows-like interface (even in Firefox 4 there remains its signs, in comparison to, for instance, Opera which I used until after an update caused fatal crashes with funny journeys to BIOS). But again, addons, that make my life much easier in some respects, are the reason why I became a Firefox user
Score one for open source software! I use Firefox 4 with Fedora 14 and it works great. I also have a special place in my heart for open-source, which is why I don’t use Google Chrome (also good software, mind you).
You have heard of Chromium, right?
Yeah, but Chromium’s a bit… crashy for me. 
I was just pointing out that Chromium is Google Chrome at its base. You said you don’t want to use Chrome because it’s not open source…but a great deal of that source code was released and turned into an open source project. That’s what Chromium is.
No arguments from me about any of the above. I’ve got nothing against Chrome or Chromium. But Firefox is a 100% open-source project, and is arguably the best browser out there with v4. Mozilla also does much to maintain a free and open web. Great group of folks on that project.