Last version of Opera without the engine re-write called Presto:
[1] 'Reflow' is a somewhat controversial topic as some people love it, and other hate it. It allows one to start reading the page sooner, but as new stuff comes in (like pictures), it can move bits of the page around when it updates the display. More noticable on dial-up connections and badly coded web pages. Opera V7.2 contains a preference setting (preferences > windows > loading) that allows the user to finely tune this, allowing both a full reflow or mimicking Opera 6's behaviour.