This gets asked again and again and again and again and ....
Anyway, best AV : Kaspersky.
Lightest AV (with a 3ghz PIV you dont need to consider this) : Nod32
Best Firewall : Zone Alarm
Best Antispyware : Webroot and Pctools (Spyware Doctor).
Best Sexurity package : Kaspersky Internet Security.
And remember, not to choose free options if you want top notch protection. The likes of AVG,Avast and Spybot cant match up with the paid alternatives. Anyway, Kaspersky has better detection rate than anything else under the sun.
And, I would strongly recomend that you DO NOT install norton under any circumstances. You friend is probably one of the many people who have only heard of Norton and thinks its the best as its the most popular. Norton is bloated, and nusiance. I still see many people saying that its un-installer screws up.