"out of the box", i think Chrome and IE9 are the most secure. only thing i hate about Chrome is the horrible spell checker. it's top notch as far as speed and security are concerned. IE9 using protected mode is also quite secure. and it has a very good spell checking addon: ieSpell. but it feels sluggish compared to Chrome; just open a new tab in IE9 and see for yourself. and it just does not feel as polished as Chrome. if someone can come up with a good spell checker for Chrome i'll be quite satisfied.