Completely agree with this, with one caveat: the only thing worse than McAfee is Norton, which honestly I now regard as malware.
There's good free anti-virus out there. Which one is the best is an ever-changing game, but AVG has been good (it's pissing me off lately though.) Avast is also earning a good reputation and I'm probably going to swap over soon. Surf wisely, be paranoid, and anytime Flash asks you to update it, say yes. Don't use Outlook for mail, and use Firefox or Opera or some alternative to Internet Explorer for browsing the web.
Protecting your laptop in other ways: if you live in an area that has winter weather, if your laptop gets cold (such as in your car on your way to work, etc.) let it warm up to room temperature before you turn it on. Also, laptops generate a lot of heat and don't shed it as well as they ought; if you're going to be using it for an extended period of time and in one place, there are things you can get to put under them that allows air to circulate more easily. Get a good carry-bag that's got some padding to it and isn't uncomfortable for you to carry.
Make frequent, multiple back-ups of your data. Dropbox has serious security issues, but a lot of people like it, so that's your call.
If you are on a college campus, where theft tends to be rampant, make note somewhere of your MAC address. If your laptop is stolen, you can usually give that info to your campus IT organization and the moment it shows up again anywhere on their network they'll nail the thief. I don't know if larger ISPs like Comcast offers that service, but they might, so it's not bad info to write down somewhere regardless.
Good luck, hope that helps!
-Suzanne
Microsoft Security Essentials is free, and good as any.
