I don't get you guys. I have no antivirus software on my PC, and I haven't gotten a virus in 10+ years. I use Outlook Express exclusively for e-mail (I don't like Firebird).
Firefox is also overrated. It uses many of the same design principles of IE (like, running code directly over the Internet and JavaScript hacks all over the place). If you search forums, you'll find plenty of posts about people having their systems attacked through Firefox. The Open Source community is just hyper-sensitive about that information getting around. If the deisign is flawed, it's just a matter of time before exploits are found. How fast they fix the problem is irrelevant as people cannot be expected to update software on a daily basis.
v1.5 also still has bugs that have been around since 0.8, plus more problems with copy/paste and hotkeys. I'm so sick of this "Open Source is always better" BS. It's the dedication of the developers that matters.
