The non-flat underside wasn't something I thought of before I got the N900, and I agree it's annoying. I quite often used to type on my N810 with it flat on a table.

I agree the USB socket should be on the bottom for portrait mode, which would also make car mounting or a desk stand easier, so you could put it in a powered mount or stand in portrait mode.

As "low life" says, ideally both power and USB would ideally be on the same side, so that a mount/stand could plug into both sockets simultaneously, easily.

If I could add one more item re: industrial design: it's not worth adding two little bumps to the keyboard letters F and J if they aren't actually prominent enough to feel without looking at the keyboard! Personally I think they should just be removed, as I wouldn't want bumps that were so big they would hurt my thumbs after a while.