My family's had good comments on "AVG"s free version. I ditched Symantec for it not long ago, and have been running it on several machines with no problems.
In fact, my mother had a virus on her system that Symantec couldn't remove. It tried and failed every time. So I uninstall Symantec, reboot, install AVG, run a scan, and it removes it without a fuss.
Slicker'n snot.