My main concern after reading your post, is that I am unprotected against current mac threats, ie. Word macroviruses, and the DNS changers.
There is no perfect protection against threats. Unfortunately the macro viruses are relatively common but the good news is they do little damage on Macs. Often all they do is replicate into each new office document (usually only a Word document.) Occasionally they break the file so that it wont open. There will also be minor misbehavior of things like memory sticks because it wont unmount normally. Of course if you pass it on to a Windows user and their AV doesn't catch it... well the sky is the limit.
As for the DNS changers the news is better. First they are rare on Macs. In fact the first one is less than a year old. Even better news - you have to install it yourself. It pretends to be a video codec that let's you view a movie but is in fact a kind of rootkit and specializes in aiming your internet queries against compromised DNS servers which can then point you to compromised versions of banks, etc. But the only exposure of this type of DNS changer trojan for the Mac comes up if you visit certain pornagraphy websites. Many of these trojans affect Windows users but the first one geared specifically to work on Macs came out last year and one syndicate is systematically pushing it through all their compromised systems. But for average people, they will never see it. It's mostly news in that something of the type now exists where it didn't before. And sooner or later someone will use the same style of attack on a wider scale.
Course these are just two of a small list of compromises that exist for the Mac. I don't have any samples of the current Quicktime vulnerabilities. It would be nice to know if Avast! can detect those.
I was wondering if there are other (safe) test files to be found, other than the Eicar.
Nope. No safe ones. The idea behind my bank of viruses is I pretty much know what they do and how to handle them. I certainly don't willy nilly use them. But it's easy to have a file sitting on a drive and aim the scanner at the file and see what it says.
If the software is not protecting my computer, then why should I use it?
I switched from VirusBarrier to avast because VB doesn't do much about windows viruses, but does protect the mac. Now, it seems I am protected against Windows threats, but not Mac threats.
Avast detects some Mac viruses as well as many Windows viruses but this is true of most AV software. In some respects Avast has an excellent reputation - one of a short list of AV software that detects a particularly nasty javascript attack which finds your model and sends intelligently chosen attacks against your version of computer for example - and yes this nasty javascript thing know about Macs. However the Avast system on Macs doesn't watch for javascript execution.
I'm here to see what Avast is going to grow like and see if I can help it. If they grow and grow well, all to the good. If they do something else, well then I've seen what Avast will do.