I recommend Sandboxie and NoScript. Using SBIE protects the system because once the browser is running under its supervision, all changes created while browsing are isolated from the rest of the system, registry, etc, that way the system remains intact. For example, if you are browsing and while visiting a site, malware starts getting downloaded and your antivirus don't do nothing, all you have to do is delete the sandbox. Once you do that is like nothing ever happened.
If you use SBIE all the time, you need to only concern yourself with files that you download, recover to the hard drive and execute out of the sandbox instead of having to be concerned about anything you do while being connected to the internet. This makes the internet experience a lot more enjoyable as viruses and worries belong to the past.
Most people when they start using SBIE, start by sandboxing the browser but keep in mind that running the browser sandboxed is only the tip of the iceberg of what can be done with the sandbox. In my case, I take everything that Sandboxie offers and use it. I isolate not only my browsers but also my EMail client, PDF reader, video players, you name it. I sandbox all programs that I normally run. The sandbox can also be used to isolate USB, CD and DVD drives.
About NoScript, in my case, the main reason why I use NS is because it helps clear websites of disturbing and annoying ads, that way is easier to focus on what I am doing. NS can be used to block not only potentially malicious Javascript but its also used to block Flash, Java, IFrames and other plugins. I also use it to block trackers and it protects against Clickjacking and XSS.
http://noscript.net/
In my case, Sandboxie and NoScript is all I use for protection, no need for anything else. In your case, if you decide to use SBIE, running your favorite AV along SBIE will be more than enough protection as the AV can handle known treats and Sandboxie will take care of the rest.
Bo