Free from malware

Firefox and Internet Explorer 7 both do a good job of keeping malware-addled sites and phishing sites from compromising your computer, but neither one is perfect, and if you're still running IE6, there's not much between you and the perils of spyware, trojan horses, and rootkits on the web.
Enter LinkScanner, which rides atop your browser and scans every web page you visit (as well as email you receive) to check for exploits. Even better, LinkScanner integrates with most major search engines to scan results after you perform a search: An icon next to each result shows you whether the page is OK to visit or whether it contains malicious spyware.
LinkScanner claims to be more up to date than McAfee's similar SiteAdvisor, and the company offered specific examples where it has been more timely. Both offer free versions for personal use and "Pro" versions with upgraded features for about $20.
One nifty extra feature: LinkScanner also exists in an online form. If you ever receive a URL you're unsure about, just visit this page and paste the URL into the "URL to scan" field. LinkScanner Online will tell you if it's safe to visit or not.
Give them both a whirl and see which you prefer. If you tend to troll in the darker corners of the web, installing one of these is a must.