Opera is world known as the most complete browser on Earth, i use it and it's just great !! i allso use Safari because it.s the fastest ! the conclusion is that Opera is the BEST! i am sorry for the others
actually, i use opera, internet explorer and firefox.
opera the most because it combines almost all the features i want (and some of them, firefox lacks) with speed and security.
internet explorer mostly for websites that don't work how they're supposed to in opera.
firefox if a website doesn't work right in either opera or IE, if i need to use downloadhelper (the only feature i'm missing right now in opera...) or if i simply have too many tabs opened in opera which i need to keep open.