>>Having the Preview Pane turned off is a more secure way to run Outlook.
>
>Seriously? lol
>
>I really cannot see myself using Outlook without the previous pane. Whenever I click on an item in the upper list, I need an immediate view of the email without opening a new window.
>
>Are you using it with that option turned OFF?

Yes.

The most common malware attack vector these days is malformed HTML, either on a web page you visit or in an HTML e-mail you receive. If you have your preview pane turned on, Outlook invokes IE to render the e-mail in the preview pane.

So, if you so much as preview a malicious e-mail that contains a zero-day exploit, you get attacked. Much better to delete obvious spam, phishing etc. from the message list without previewing.

Outlook has some mechanisms to help mitigate some of these attacks, but it's by no means perfect.

Speaking of spam, there are ways for spammers to craft their messages so that if they get rendered on your PC, a notification goes back to the spammer confirming that your address is good. Then you get more spam.

So, if you're concerned about security and spam, running with the Preview pane switched off is a no-brainer AFAIC. For similar reasons, my primary browser is FireFox because it supports the excellent NoScript add-on.