This may be something only I've experienced, but I've found Google Chrome to be more secure than FireFox.
Granted, my wife's on an older XP machine, but in her ridiculously innocent browsing, I'd wound up needing to reformat multiple times while she was running firefox due to virus troubles. In spite of her having the same security measures of my machine (which at the time was a combination of Avast, Kaspersky, and Malwarebytes). I suppose it could be her running on an older XP machine, but regardless...
I finally said to hell with FireFox, hooked her up with Google Chrome, and she's been sitting good ever since.
I've always used Opera, but I've considered switching over to Chrome.