I mostly use IE, sometimes Firefox and Opera. depends on what I'm doing. Yesterday I ran Spybot and Ad-Aware and both came up clean, and that's after a week of browsing. I do have MS Antispyware and Spybot-SD running in the background though.
All browsers have vulnerabilities. The more popular the browser the more vulnerabilities and criticism it will attract. Firefox has it's share of zealots in much the same way the Mac does, perhaps it's the underdog insecurity psychology at the root -dunno. To hate something (like IE) is not productive. Both do a job, personal choice is down to you
Andrew Kantor writes "What is wrong with Mac users and Apple fans? I mean that -- I've never seen the like. Calling them "blind lemmings" doesn't always seem strong enough."
I tire of citing statistics, so I won't... Go check them yourself if it's really a concern for you. Fact is, FireFox has almost 0 of the most critical vulnerabilities unpatched, whereas IE has about 20-30 unpatched critical vulnerabilities. The security in Firefox doesn't come from fewer flaws, it comes from the speed at which flaws are patched once they are discovered. That means that there is almost never a chance for anyone to actually deploy exploits based on a FireFox flaw, while there are still numerous IE exploits floating around in the wild that work on a *fully patched system*.