And actually it would be probably better to refer to this feature just as 2x scaling and not pixel doubling. It performs pixel interpolation, so the picture looks smooth. So Nokia 800x480 screen has advantage over devices having 320x240 resulution as we also get some kind of postprocessing and get better picture quality

Also I did some benchmarks for 640x480 video with mplayer, looks like Nokia 770 still has some potential of handling high video bitrates and resolutions. If it gets some more video decoding optimizations and hardware YUV support, probably even watching nontranscoded 640x480 videos can become a reality. And if we manage to get scaling work done by DSP while having ARM core responsible for video decoding only...