Here's my take:
9 in or higher-----> tablet pc (iPad for now or convertible tablet/laptop)
4.5 in to 7 in -----> pda or mini-tablet pc (i.e. galaxy tab, dell streak)
3.5 in to 4.3 in----> smartphone,ultra-mini-tablet pc (iPhone, iPod touch)
I prefer ultra-mini tablet instead of pda. iPhone and iPad is the best combination.
9 in or higher-----> tablet pc (iPad for now or convertible tablet/laptop)
4.5 in to 7 in -----> pda or mini-tablet pc (i.e. galaxy tab, dell streak)
3.5 in to 4.3 in----> smartphone,ultra-mini-tablet pc (iPhone, iPod touch)
I prefer ultra-mini tablet instead of pda. iPhone and iPad is the best combination.