GMail

Hardly need to tell you what this is, eh? You may have found a particulraly interesting use of some of its capabilities though - I'll add one to start with

If you're having trouble accessing your organisation's e-mail account outside the office or struggle with the grotty Web Outlook interface in non-MS browsers, or simple like really fast mail and room for those huge attachments then why not adjust the settings in GMail so that the address shown as 'sender' is you@yourorganisation.ac.uk or whatever. GMail will check you're not pretending to be the Principal, by the way, so don't try that one!