I actually like the N900 screen size. I was waiting for the release on N97 to replace my N95 and now I will wait instead for this N900 to replace the N95.

Today I use very little my N800, as it is too big for my pocket (I have small pockets) and the screen a bit too small to browse the net (i use my 7" tablet most of the time, it is comfortable enough to fully replace the pc).

Most smart devices in the market have the screen either 3.5" or 7" (or bigger).
I believe Nokia will later release a 7" tablet with Maemo. It would complement this N900.