The most annoying ringtones

The three most annoying ringtones I've ever heard, in ascending order of irritation:

3. A recording of incomprehensible toddler babbling. This kid might have been trying to say "hello", or might just have been yelling into the microphone. I'll never know.

2. The sound of a smoke alarm with a low battery. Aside from being a bizarre choice, it was piercing like the call of a bird of prey and audible across the entire office floor.

1. That frog. You know the one I mean. The only place I've heard it recently is in my mind, which just goes to show how potent it was. I don't tend to really dwell on it, but every now and then it surfaces in my memory and shatters my zen-like calm.

Mokalus of Borg

PS - I haven't compiled a list of the best ringtones.
PPS - In my opinion, though, the best ones are silent.