From Sergejs' article:
However, the presence of a large touch sensitive screen considerably limits the creative freedom of phone designers. The very way of approaching a design in phones has dramatically changed over the past four years. Sadly that also means we will probably never see the return of such bold and daring ideas that we saw embodied in the Nokia N90. Coming from this, it’s easy to understand why the Nokia N90 is such a hot little collector’s item these days.
In the center of Nokia N90 transformations lies its 2 megapixel camera. It was the very first Auto-Focus camera in Nokia phones, and it was also the first phone camera ever to come with optics from the world class manufacturer, Carl Zeiss. The camera is a nifty little monster that illustrates perfectly how even just 2 megapixels can provide impressive results if given good quality optics.
History fans might also like to check out our own review of the Nokia N90, back from a bygone and bizarre age when we let Ewan loose reviewing camera phones....!
Personally, I loved my N90 and it was my main smartphone until its successor the S60 3rd Edition N93 arrived, with similar form factor but much higher specifications (3 megapixels, VGA shooting!!) in 2006.