Don't use more then one av, firewall and anti spyware, more app don't mean more secure, they mean more conflict.
all you need is a good one.
eset smart security and malwarebytes or spysweeper will give you all the av/firewall/anti spyware you ever need.
but keep in mind being safe and clean is 80% dependent on your commonsense and 20% on what apps you use, lets say there was one av that was the best and one firewall that was the best and one anti spyware that was the best, if we have all 3 of those, and used very little common sense, within minutes if not seconds, our pc would be infected or hacked and ultimately vulnerable.
So its not about which app or how many security apps you have, its about how much commonsense you use.