I won't go into failure rates and all that, everyone knows that the real figures are way higher than what M$ says.
I too believe that nearly all the problems with the 360 are heat related. It doesn't take a genius to see that a couple of fans spinning at fairly low speeds aren't up to the job of cooling one of the most powerful processors and one of the most powerful GPUs going.
However, mine's been going strong since March 30th

Not a sausage, apart from the odd glitch in PGR3 sometimes. I get weird coloured triangular shapes. But as soon as I position a fan perpendicular to the fans blowing air out the problem is solved. Every other game works with no problems, even the supposedly more demanding Dead Rising.

I guess I got lucky; though, by my gamer score, it's clear I don't spend too much time on it, so that may have a lot to do with it I guess.