well...as those who have seen my posts for years might guess, I 'have' almost all of the browsers.

To me, security is 98% what firewalls & Anti-virus..plus anti-malware programs one has. (and of course, avoiding bad web sites)

I use Opera (in 3 different versions) maybe 70% of the time, and Firefox 28%. I am also watching the development of Google Chrome (not impressed so far) and SeaMonkey...which is Firefox on steroids with email and newsgroups and RSS feeds all built in. SeaMonkey will use all the Firefox add-ons. (and I have two other odd little browsers which are small & fast- K-Meleon & "Off-by-One". They do most stuff ok, I just forget to look at them.)

Now.... Firefox is the one I keep set to do YouTube, my bank, my HMO...etc....and Mudcat, if I happen to want to look when I have Firefox open. The thing is, so many sites want to use javascripts and pop-ups..etc, that I keep Opera set to refuse such things and refuse ads. It's easier to open Firefox than to make Opera 'open' to them all.

Like Jeri, I have all the AV & firewalls up to date, and have only had maybe 2 virus warnings in several years. Also like Jeri, I do love Firefox for its flexibility in what you can train it to do, but I MUCH prefer Opera for the particular sorts of internal navigation I do (forward, back, switch between tabs, move between clickable links on a page, and a couple other things .. are all done with keys 1,2,Q,W,A,Z right by my left hand. I can also hide ANY of my toolbars in Opera with one click by a special javascript addition.
That being said, if Firefox added those tricks, I'd be 95% in Firefox.