Wikipedia says

http://en.wikipedia.org/wiki/List_of_displays_by_pixel_density

HTC Desire has 252 Pixel Per Inch (PPI) while the N900 has 267 Pixels Per Inch (PPI) So the PPI ratio of N900 is higher, even though the Desire is S-LCD versus the LCD of N900. Does that conclude that the Image Quality and the display on the N900 would be better than that of Desire's even though the Desire is S-LCD.