Best cpu for AM3 socket.

Parents are forcing me to upgrade there PC, they refused to let me upgrade there motherboard (god plz kill, there arguing with me even though Im paying for the upgrades) anyways there motherboard has a AM3 socket so whats the best one out there?

Oh and the reason they're not letting me upgrade there motherboard is because there scared it might give them a virus, and Im not in the mood to argue with them about this because they argue in circles (plz send halp)