Binos,
That's good news about your iMac, apart from the screen issue. Have you tried zapping the PRAM & NVRAM? It might solve the problem:
http://docs.info.apple.com/article.html?artnum=2238
I think a letter to Apple is worth it – Australia is a new territory for their own AppleStores. Resellers in the rest of the country will need to be singing from the same hymn sheet. Here in the UK, many resellers now have "Apple style" shops, remodelled in association with Apple and the staff having received training from them as well. They are known as "Premium Resellers". It will be more important to Apple now to see where the resellers in Oz are going wrong so that service can be improved.
AppleMacster