Should I pay for antivirus and an extended warranty?

Episode 1142 (2:06:58)

Debbie from Ontario, CA
Asus Transformer

Debbie got an Asus Transformer notebook and she's wondering if she needs the extended warranty. Leo says that the Transformer is a great laptop, and the warranty is just an insurance plan. They are a profit generator for the company that sells them. Leo prefers to self insure.

If she's going to get an extended warranty, she should get it from the manufacturer. The peace of mind factor is difficult to calculate and may be worth it. What about antivirus? Leo says that Windows 8 comes with Windows Defender, and that's more than good enough. But even the best antivirus won't protect her from her own behavior.