Oli, sorry to hear about your experience, that is crazy! With an Apple warranty plan in place Apple is really saying to you that it's not covered
This is the kind of story that continues to support my personnel belief in the way I go about a computer. I have had the best of luck the last 10 years building my own PC's. I have built 5 PC's in that time and my XP's were very stable, then last summer I went to Windows 7, which was the best thing I have done. I can load it up with RAM (12gigs), i7, 64bit, GTX 470 and after up and running it ended up costing just under 2K.
I have owned, and still do, a titanium G4 which I liked but eventually was just to slow for me and so I shelved it years ago then 2 years ago I bought my wife an imac, I'm not much of a fan anymore. Apple does produce wonderfully aesthetic products but I have a hard time paying what they want for them. When I compare what I can get in a windows machine I end up liking the cost to quality & speed ratio with the windows machines. I also like the building the machine this way your machine does not come with a load of junk you don't need or want on your machine and you can install what you need and only what you need.