Even though it's got all these things; it feels incredibly lightweight, and nothing like IRC, BitTorrent etc happens unless you tell it to (so it doesn't use ++++RAM)
Opera is ugly, clunky and not expandable. Firefox 3 gives you a better overall experience and is much more user friendly. The every day user, even power users, have little to no need for Opera. That's why it'll always be 2nd best, 4th popular.