germanjulian said:
simple. works flawlessly. takes no system resources. No virus since 2 years.
*That you know of.
Although I agree with you that being smart, not using IE, Outlook, and using a firewall will cut your chances of getting a virus down to very little, you still have a chance of getting one, even ones that you cannot see. There are more and more viruses, worms and trojans out there that are targetting exploits in non-microsoft programs. Namely mozilla-based browsers, which make up the majority of non-MS browsers, and numerous email clients.
If you have a router, you are not safe from friends who come over and plug in, if they are infected with something network-transferrable, then you will get it if there's not a windowsupdate for it, or if it propogates through shares, you have a good chance, unless you have disabled windows file sharing.
Knowing what's running in task manager is nice, but processes can now hide from there. If a virus infects a file like explorer.exe, when that file executes it should run like normal, seen as a legitimate file, but still can exhibit virus/worm/trojan properties.
To everyone who is not running a virus scanner: Yes, you are living on the edge.. woo, but even knowledgeable people can catch viruses, in which case you are only part of the problem. Even knowledgeable people with virus scanners still get viruses. It's especially the case if you have a lot of computers or laptops moving in & out of your network.