I really like Norton Antivirus 2011. Note I said Norton Antivirus, not Norton 360 or Norton Internet Security. The suites may or may not be any good, I can't vouch for them and would encourage you to read some reviews online before you decide to buy one of them. You can get just the antivirus for $40 from their website but if you go to a physical store like Best Buy, Target, or Wal Mart, you can sometimes find it on sale.

You can survive with Avast! which is available for free if you prefer to save the money. But Norton is less resource intensive, gets updated rules pushed to it more often, and generally receives better reviews.

Although current versions of McAfee have also received good reviews, I have personal experience with it that keeps me from being able to recommend it. I had a situation where the latest version of McAfee (this year's) detected a trojan and warned me it had been installed, but failed to stop it from happening and then failed to clean it up afterwards. If I didn't know as much as I do, I would still have that trojan mistakenly believing that McAfee had gotten rid of it. Serves me well though, since I was acting against my morals by trying to find a pirated version of a tv show that I wanted to see and wasn't available in my country (I never did find it, found the malware instead).

When it comes to using a laptop, it is also important to be sure that you get a good wireless router and that you enable WPA2 encryption with a strong password.