From the looks of things, I'm going to have to state the actual unpopular opinion about the Gamecube, at least around here: The Gamecube is the weakest Nintendo console by far.
You know, I had just seen the Wii U thread and remembered that I completely forgot about the Wii. Must have blocked it out. So I'll amend my statement: the Gamecube is the worst Nintendo console that didn't pander to casual gamers to print money.