I've got the answer to your prayers.
Go into Outlook Express... Tools->Message Rules->Mail.
This is the best feature of Outlook Express.
You can configure it to perform various actions to any incoming mail. For example, to solve your problem...
"Apply this rule after the message arrives
Where the Subject Line contains 'Viagra'
Delete it from server"
BAM. No more Viagra mails.
Do the same for shit like "home mortgage," "re-finance," "bad credit," "xxx" blah blah blah and you will never see junk mail of that type. Have to be careful, though, because the machine can't tell whether it's your friend e-mailing you about his success with Viagra or something. Fortunately, I don't have any friends who use Viagra (except WODIN of course, but he doesn't e-mail me), so I don't have to worry about messages getting accidentally discarded.
Good luck avoiding the spam... if only my real mailbox had such a sophisticated filter.
-Warik