AGI will only be Friendly if its goals are the kinds of goals that we would want it to have
At the risk of losing my precious karma, I'll play the devil's advocate and say I disagree.
First some definitions: "Friendly" (AI), according to Wikipedia, is one that is beneficial to humanity (not a human buddy or pet). "General" in AGI means not problem-specific (narrow AI).
My counterexample is an AI system that lacks any motivations, goals or actuators. Think of an AIXI system (or, realistically, a system that approximates it), and subtract any reward mechanisms. It just models its world (looking for short programs that describe its input). You could use it to make (super-intelligent) predictions about the future. This seems clearly beneficial to humanity (until it falls into malicious human hands, but that's besides the argument you are making)
Here's my draft document Concepts are Difficult, and Unfriendliness is the Default. (Google Docs, commenting enabled.) Despite the name, it's still informal and would need a lot more references, but it could be written up to a proper paper if people felt that the reasoning was solid.
Here's my introduction:
And here's my conclusion:
For the actual argumentation defending the various premises, see the linked document. I have a feeling that there are still several conceptual distinctions that I should be making but am not, but I figured that the easiest way to find the problems would be to have people tell me what points they find unclear or disagreeable.