As An Ordinary User What SW
Word, Excel?
Real Player - rm?
MP3?
MSN IM?
BT?
Wireless connections?
They all run on Mac and Mac files can be SAVE AS window files.
Mac OS X is good platform and a lot of things can be done on it.
As an ordinary user, most of things she/he can't share with PC-friends are virus, troj. 3721s, :-).