I used norton, mcafee, kaspersky, webroot, avg, etc.
If you have norton, mcafee, or avg, you may as well not have antivirus/internet security installed. they easily missed known threat if the attack came in masked as known/trusted provider (i.e, adobe, microsoft backdoor,etc).
Kaspersky is a very good antivirus, however I experienced multiple occasion where it detected virus, but the attempt to remove it failed and the virus ran loose.
Webroot is a different story. It used to be only a spyweeper, in which it detect adware, cookies, etc and remove or block it from your computer. Webroot evolved and added antivirus feature, and it is also very good. The downside, it could really slow your computer down.
Webroot now have 60 days beta testing internet security suite (spysweeper, antivirus, firewall, window washer, the whole nine yards). I love that one of the feature is marking your searched website as safe, unknown, or known threat. However, it can really slow your computer down. If you have super spec computer, I 100% advise you to go with webroot. its free for 60 days and if you dont like it just uninstall and get other stuff.
If you want something that doesnt eat up your system's performance, I would do separate software
.
*use Webroot Spysweeper for adware,cookie,malware protection
*use either kaspersky antivirus, trendmicro antivirus, or sophos (you can get this for free for home user from sophos.com its supergood)
*download webroot window washer anyway cause it doesnt have to run all the time so its always handy to have
*use whatever firewall you want.
many people say separate programs slows your pc down, its actually quite the opposite. As soon as I use internet security suite of any kinds my computer's performance degrade 30%. different sofwares works more effective for me.
another thing, some virus now attach themselves to antivirus. sophos/webroot are ones that so far has not been listed as being vulnerable to this threat.
Based on personal experience, I would advise against updating you windows OS from the initial installation and turn off auto update. Almost all backdoor attacks hits right after some updates with loopholes are released to public.
There's 5 computers in my house, 3 has updates disabled, 2 auto updates enable (vista and Win7), both of my auto update laptops got backdoor attack immediately after update. The malware posed as microsoft system, certified, and took over the computer's admin and enabled remote access.
At this point I had to run rootkit analyzer and go in one by one removing it. The never updated computer NEVER ever have problems or even came close to being vulnerable.
I hope it helps.