OK, a few notes of my own.
First, I've always used the preview pane and never got infected. Make sure your Antivirus is up to date and you'll have no preblem.
Second, about Outlook or OUtllok Express. Depends. Do you need a calendar, agenda with reminders, notes and tasks tracking? If yes, thye Outlook is far superior. But if you really just want to send emails, then it would be absurd to use Outlook.
But, if you decide to use Outlook XP, here are a few notes.
1- Outlook XP will not let you receive any executable or script files. Outlook will block and not allow you to receive any files that has the extension EXE, BAT, PIF, COM, SCR, and a lot of others. The stupid thing is that there is NO option in Outlook to turn that feature off. There is of course a way (there always is) but it involves playing in the registry.
2- Outlook XP has a bug with attachments: sometimes they just don't show. I'm not talking about the executable that I mentionned in the above point, but about attachments in general. JPG or whatever. Most of the time it's fine, but once in a while (I dunno, once in a 100 maybe?), the attachement are there, but there is nothing telling you that there is an attachment to the email. The only way to know is to notice the file size of the email. Then go to the file menu and select save attachments, and there they are. Anyway, it's a bug. I've seen it happen on a few different computers so it's not just me.
3- In you Write Email options, make sure you do NOT use Word as your email editor. It really slows opening a new email (sice Word has to open every time you want to write an email), and there is absolutely no benefit anyway.
That's it I guess. Oh and despite my notes above, I do love Outlook. That's what I use and couldn't live without it.