Danny,
I agree with all you said, however even when you are expecting an email you must still be very careful.
I have only ever had three separate viruses reach my computer over the years, luckily all stopped by my MCAfee Activeshield before they did any harm.
One of them, several years ago now, was from a very reputable Hotel in Hong Kong. I had sent them an email asking for some details of the Hotel for a planned trip. When I received an email reply, with attachment, the next day I went to download the attachment, as I had asked for this information, and Activeshield warned me NOT to as it was infected.
So even an email that you are expecting, from a reputable source, can still be trouble.......
Best regards,
"lame"