After I got my Nexus 10, I immediately installed Avast Anti Virus that I use on my W7 computers. There is a version for Android. The way that Android works, A firewall is not effective unless you have the device rooted. So far Avast has not found any malware on my device. I installed Advanced System Care on the Nexus 10 too since they now have a version for Android. With my device at least, it is all good so far. It seems the best chance to pick up malware or viruses is when you actually use a Browser to connect. Most of the connections seem to be via the app which uses it's own internal browser evidently. That may be the reason that tablets seem to safer. With a W7 machine, you usually get to where you are going through a browser such as IE, FF or Chrome. If you get to an unsafe site with a browser, you will definitely have to have the firewall and anti virus active. The Internet is wide open and there are lots of sites that take advantage of that by installing malware if you let them. A good Firewall and Anti Virus will warn you about that, and you can abort the installation. Even Mac's OS X is vulnerable to malware as has been reported recently. With Java and Flash for Windows, there is even a greater chance of malware getting in especially if the 3rd party programs aren't up to date. If you use Windows, install the Free Secunia PSI program that will inform you if any of your programs are not up to date. I use that on both of my Windows 7 Computers. If PSI can update program, it will otherwise it will inform you that you have to do it manually.