At my old school,a lot of kids used Norton (don't ask why a middle school needed laptops.) I always saw Norton do something really stupid, like lockdown you computer "because you had a virus" instead of just deleting it. And it would always keep it that way, basically saying "Too bad :D". I've had mcafee for ages, and it's served me well. I use the old one though.
But, I have separate scanners for bots and spyware, so... take that information as you will.