Bouncing Zabaglione Bros.
Legend
As people are trying to point out to you, for the vast majority of users, who've had 1 failure or less, the value users have gotten from the box outweighs the small annoyance caused by having a failure, and it's ridiculous for YOU to tell those users they have a lemon.
A lemon is a product that has a major design flaw that results in critical failure. The Xbox360 is exactly that. You're trying to make out that one failure is acceptable when in actual fact one is too many. In practise a lot of people have had more than one failure.
A lemon is a product that fails, and is defective, repeatedly. So, if someone returns their 360 4 times, and it keeps failing, then you can call that a lemon. Sure. But you gotta also have a little perspective, and realize that is probably 1-2% of the userbase.
Microsoft's statements and billion dollar repair fund says you're the one who is wrong here and is exaggerating the robustness of the product with only your own "good" experience of a single critical failure to go by.