I have Norton Anti-Virus version 12.8.0.4. I was told it includes Firewall.
I use Avast on my X64 Machine, Norton 360 on the XP Entertainment Computer and McAffee on a third machine. All three are good but Norton has more bells and whistles. Despite what some people say here some of Norton's software is pretty damn good.

Then you should be alright. I’d still recommend getting Spybot Search & Destroy, and Ad-Aware. Both Free.
Now, let’s take this to another level. The above is fine for protecting your PC from unwanted intrusion. But what do you want to insure it continues to run well? A couple recommendations:
1) Diskeeper. It’s software that runs in the background and keeps your hard drive unfragmented.
2) RegCure. The best Windows registry tool available.
Both cost $ but are well worth the price.
Finally, the best & easiest way to backup/restore a hard drive is to have a separate drive available (external) and run Acronis True Image (also $ and available online). Acronis will write an image of your hard drive to the separate disk, and create a recovery CD. If you have a problem (as I did earlier this week) you can use the recovery disk to reformat your hard drive and reinstall everything VERY quickly. An absolute must for any serious computing.