Aside from the typical inherently unpleasant tones, shovel on concrete, dry fingers touching hard foam, anything touching corrugated tin, fingernails/chalkboard, emergency broadcast alert tones etc. I see what you're going for.
-the sound my tv makes during those unnecessarily long birth scenes on television shows & movies.
-most peoples' ringtones, especially when they delay answering to let the song finish.
-women talking while when I'm eating. That sounds worse than it is- maybe the human male voice would bother me as much, but it seems like they generally don't talk when I eat. Or I can't remember it. Or maybe they're always eating around me too.
-superfluously loud exhausts (i get the performance angle of some, & safety for motorcycles etc. but I actually know motorists who, even if all else were equal, would prefer, would pay more to hear it. I'm weird, willing to pay more for LESS noise.)
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http://www.youtube.com/watch?v=mFA59OtWh5c
^is the all time worst. The sound of every radio in town switching stations. No one can listen to the entire 30 seconds, but see if you can make it to the man's verse.