This is really interesting! It's great to have so many different people and ideas on the board, as then you get answers that come from every perspective. So it turns out that European speakers of English and their antipodeans are the ones to spell with an "e", while Usamericans (what about Canadians?) prefer not to have the "e". The philological explanation makes sense... I think I understand that the *orthodox pronunciation for a "dg" cluster with no "e" would normally be a hard /g/ and not /dz/?

Nicholas, I see that you are in London. Maybe you can solve what is one of life's great unanswerable mysteries for me. How do you spell and pronounce "Edgware Road"?

Thanks for all the other words I hadn't thought of.