As for sending, I rarely send an actual file attachment, just an email with a link to the file saved in Gdocs.
I think - but am not sure - that Gdrive could help to make this easier to do. Still experimenting with it though.
I dunno, I trust a nice honest email with an attachment more than "some ethereal link to the Cloud". I am sensitive to Cloud Lock-in, it feels like that Arnold S. movie on Mars where they started charging for Air. I just need to ditch the emails from 2007-2009 and then I'll be okay. Save, Save Attachments, then file them.