What everyone said. :)

And for video: .wmv and .mpg can be opened by Windows Media Player and .mov can be opened by Quicktime Video Player.

One warning about opening emails in HTML as opposed to text. There is a certain degree of safety about having all emails open in text compared to HTML - since you don't have to worry about malicious code with text. Also, you don't have to worry about spoofed links with text emails compared to HTML links. 'Course, you miss out on all those cool links and graphics when you open emails in text.

Masaki