Depends on your surfing habits.
The only things I have running in realtime is my AV (AVG), Spywareblaster, Spywareguard, and Spybot's TeaTimer, and I haven't had any problems in 4 yrs, but then again, I'm careful about what sites I go to.
Something to help in deciding which sites to go to, and which not to go to, that I also use, is Siteadvisor
SiteAdvisor is a downloadable tool that works with Firefox, and IE, to help you, stay safe while you browse, stay safe while you search, and click to see a site's report page.
Red sites - stay away from
Yellow sites - use caution (read the report page on the site, and decide for yourself)
Green sites - good to go
I see you use Firefox, so download the Firefox extension.
If you decide to use SiteAdvisor, and a new version comes out, don't
Uninstall it, then download and install the new version.
Some people have been having problems with the updating process.
Here's a good site to go to, to check questionable links:LinkScanner
Why use LinkScanner?
Cybercriminals use "lure" sites to attract web users to sites they have invisibly infected with exploit code. This exploit code is then used to infect users' PCs with drive-by downloads of spyware, rootkits, and other malware.
* Just because you click a link doesn't mean you'll land on the site you thought you would
* Just because a site looks innocent doesn't mean the underlying code is harmless
* Just because a search engine serves up a listing doesn't mean you can trust it