What are the most common failures of laptop security?

Some of these are physical handling issues and some are web-surfing
issues. If you get these right, you have more than half the battle
against hackers won.

10. Go to all sorts of sites and leave your personal information
there.
9. Dump your coffee in the keyboard occasionally.
8. Leave your laptop baking in the trunk all day.
7.5 Surf unsafe sites (porn, hackerz sitez and so on)
7. Download anything that is free, with no regard to whether you
trust the site owners.
6. Avoid using a software firewall, that can block some infections
and (if your laptop is infected) keep you from infecting others.
5. Let your anti-Virus Software expire, or never update the virus
definitions.
4. Set the ATA Password on your BIOS and forget the
password. The first half is pretty good security because it stops
anybody from accessing the data in your hardrive without disassembling
the laptop, but forgetting the password means an expensive trip to the
authorized repair center to have the password cleared.
3. Open all attachments, regardless where they appear to
originate. This is an excellent way to get and spread viruses and worms.
2. Choose a blank password or set the machine to log you
in automatically with no "log-in" dialog box. This is dangerous on a
physically secure computer. A mobile laptop is usually in harms way,
even if the harm seems harmless, like letting your niece play with your
computer. (Ask me about the time my niece set the bios password
accidentally on her mom's computer sometime)

and

Number One

Leave your laptop where it may be easily stolen!

(repost from Tech_Answers http://tech.groups.yahoo.com/group/Tech_Answers/