Is an Antivirus really necessary?

For unexperienced user antivirus is very important. They do not know what is a virus, how can they get them ... They just open a file and boom ... suddenly something goes wrong.

 

From the following

1) Visiting sites with IE that exploits unpatched bugs

2) Bugs in OE and Outlook that automatically open attachments in preview mode

3) From downloaded stuff.

Personally I think we should make a point to differentiate between worms that spread primarily through email and other forms of malware.

The former is pretty easy to avoid if you use the correct email client and exercise common sense, the latter is harder espically if you download a lot of things on the net,