iPhone: Very Fast, smooth 2D inertial scrolling with just a flick of the thumb.
Nokia: If you hack root access, install terminal, learn vi, and edit an .ini file you can get slow, clunky scrolling with the d-pad. Apparently there is still no scroll wheel.
iPhone: Multiple ways of nearly instant, continuous zoom. Just double tap to make a certain column of text readable (depending on the web page). Nokia: A few pre-set zoom levels that are unaware of the structure of the page. Usable via keys on the top, or several taps away, in a menu.
Also, the on-screen keyboard on the iPhone *IS* useable. It's the best on-screen keyboard, I have ever seen. IMHO, the finger type thing on my N770 was 100% unusable.