I've been recommending AVG Free, Spybot search & Destroy, along with Ad-adware free and spywareblaster to my clients for the better part of 15 years.
My clients and myself have been more then happy with how these programs work, and not one has ever been compromised, while using them.
You don't need all these programs. Currently I only install AVG Free and Spybot for malware. If the customer wants more backup protection then add ad-adware free and spywareblaster. I've found that Avg Free and Spybot do the job just fine, and you don't really need the others, but it doesn't hurt to have backup protection either.
For firewall protection , I don't recommend windows firewall. It isn't very good as stopping out-going connections. I recommend using Comodo. It works rather well, especially if you disable the 'defense' portion which will drive you to drink heavily, and really isn't needed as you already covered by AVG Free and Spybot.
If you have to you can use Zonealarm free, but since ZA has a nasty habit of loading stuff along with Zonealarm WITHOUT informing you, I no longer trust them.
Spybot: (make sure you use teatimer which comes with it)
http://www.safer-networking.org/en/index.htmlAVG Free: (they also have free rootkit and spyware programs but haven't tested them much so can't say how good they are yet)
http://free.grisoft.com/doc/products/us/frt/0Ad-adware:
http://www.lavasoftusa.com/Spywareblaster:
http://www.javacoolsoftware.com/spywareblaster.htmlComodo:
http://www.personalfirewall.comodo.com/Zonealarm Free: (Look all the way to the right for the link)
http://www.zonealarm.com/store/content/catalog/products/trial_zaFamily/trial_zaFamily.jsp;jsessionid=Hz2dsbwK1c0W2gNIlrajhzYsP40kdm5XEHDICG0wZhH3oagAZrh7!-1199446515!-1062696904!7551!7552!NONE?dc=12bms&ctry=US&lang=en&lid=db_trial
Wabbit
Rolling Thunder