Share to Picasa or some other sharing site for images and videos. For sending non-multimedia, email is good.

Problem with file sharing is that few people have an account with <whatever it does the trick>. Email stinks, because of size limitations and spam. Bluetooth is slow. Chat is not supported, since there are millions of protocols.

What you need to consider is what the other party has available. If they have email, email. If they have YM, monorail (I think it works with YM). If they have none of these but have wifi, perhaps you should convince them to join a file sharing site, there are plenty out there.

Common ground.