I've also had a crank failure, and since then it has become my worst fear.

I was "lucky"; I was only going about 11 mph up a hill but out of the saddle. Even thgough I was going slowly, I still managed to mess myself up and take off alot of skin. When the pedal and bit of crank came off, the pedal slid out when my foot and pedal hit the ground...HORRIBLE.

Just think about: if you're out of the saddle and sprinting at 35mph, then you break a crank or a pedal, you've got nowhere to go.....BANG.

At least if you break a chain you've still got something to support your weight.

I can't think of anything worse to break than a pedal or crank in that situation.