I will use different models for my game. High poly models for secuences and low poly models for the game itself, like programmers do in some game consoles.
If i want to aim this game for PSP and PC, what do you think is the best polycount for high and low models of the game?

For example Final Fantasy X use 3 different models for each character, one for battles, another one for scenes, and another one for the game itself.

Do you think i can use 15000 poly for an high poly character keeping in mind that it will not be moved but the player, it will be used to make cutscenes in different areas?