Is .txt, .exe, and .doc compatible with Mac OS?
All but exe. are compatible.
Does RapidShare manager work on Mac OS?
Not sure, If not there are other manager which are compatiable.
Does .avi work on Mac?
Yes
Are there any Video players on MAC OS, like AllPlayer, Vplayer, Media Player Classic on Windows?
VLC player is my favourite.
I can't find a picture, but in Macbook these icons were white/grey.