Nice. Very nice. The Xbox-Linux / Free60 team around Michael Steil has published a paper / wiki page called 17 Mistakes Microsoft Made in the Xbox Security System. I'm currently reading the paper, but I'm not quite through yet (the PDF is 13 pages long). It contains a very detailed analysis of the 17 types of mistakes Microsoft made (they made most of them multiple times)...
The paper and the findings will be presented at the 22C3 in Berlin — this is one of the lectures I will definately be attending, that's for sure!
Quoting from the article:
"[Conclusion: ]The security system of the Xbox has been a complete failure.".
Also nice: the earlier (now obsolete) version of the paper was called The Hidden Boot Code of the Xbox — or "How to fit three bugs in 512 bytes of security code" ;-)