If I stick my Sony Ericsson w80i into my PS3 via USB, what can I expect to happen? ?

May be...

(Mainly because when I stuck my 2GB SansaDisk into it, the PS3 formatted my mp3 player and erased all my data.)

Switch ur phone to usb mode or media transfer w/e. Then u should get a message saying W80i device( mine says "USB Device(N95 8GB)") press triangle on it from the right menu, if u want to transfer music then from ps3's music menu scroll up and press triangle on the new device that appears and select display all, then look for the music/sounds folder...i dont know anything about the w80i so i cant tell u what folder ur music is in.

you might destroy the earth... don't do it LOL !!

only kidding.. it might charge the thing up !

it will charge up probably