Here is how I do it:

- NoScript >>> A Must-Have! This add-on alone eliminates majority of the threat before you even encounter them.
- WOT (Web of Trust) or BrowserDefender (both work with FF and IE) >>> Another Must-Have! Great on spotting phishing sites, links in search results and even links embedded in e-mails when using Yahoo, Google, etc.
- Adblock Plus >>> A Should-Have! Strongly recommended. Useful in eliminating distracting ads plastered all over web pages and then some.
- Flashblock >>> More convenience than security, still useful in eliminating annoying flash animation and videos.

Here is a screenshot of the Firefox Add-ons I typically use:


Red boxes indicate must-have security add-ons, the ones in blue boxes are recommended but not a necessity by any means.

The top 2 are definite must-haves for Firefox users and either WOT or BrowserDefender for Internet Explorer users imho.

Additionally, for all users Spybot Search and Destroy's SD Helper feature is a really good thing to have on.
First the "Advanced Mode" needs to be turned on then it can be seen under Tools > Resident section:

It simply created a new CLSID (apartment thread) in the registry which functions as a typical BHO (Browser Helper Object):


Also Spybot S&D's Immunize feature or SpywareBlaster is very effective protection against known bad sites and malicious ActiveX content. It is even possible to have both. Both of them modifies Hosts file along with adding known bad domains to "Zones" section in the registry.

And my final recommendation would be to insert the list of known malware sites into the Hosts file for the most practical and effective prevention.
A co-worker created a script which connects to MDL and gets the most updated list of bad domains and adds them to the Hosts file after it makes a backup copy of it for un-doing the changes for any reason.
To get more info and download this script, please see the adjacent post.

~TL


PS. The purpose of this post is to share a few pointers on how to make your browser and browsing safer, more secure.
Everyone should have a reputable virus scanner installed and equally important thing is, it should be kept up-to-date!