Blizzard's European Customer Support team has invited players to make a New Year's resolution that we at WoW Insider can definitely support. It's easier than giving up chocolate, and probably more useful than that gym subscription you were planning on getting.
Following the link in the tweet above will take you to their page on account security that is just packed with helpful tips to secure your battle.net account, and your computer. Some of the most common causes of account theft relate to lax security on the side of the user, and following these tips can really help you avoid that.
There's also legitimate links to all the major sources of free anti-virus software, and the article is packed with other tips to avoid things like phishing sites, spyware, and malicious processes. In the absence of physical items on the battle.net store, there's also advice on retailers that can sell you authenticators.