The ATV "In Colour" ident used to scare the living daylights out of me when I was a kid. I couldn't look at or hear it without getting shivers till about 7 years ago.
Something about the circles growing, and the music, which also seemed to "come towards you".
I used to have nightmares about the thing coming out of the screen and hovering in mid-air in front of me, halfway between the screen and my chair. I used to dream of seeing the symbol hovering in front of me whilst sitting on a toilet (a strangely recurring dream), and of just hearing the jingle whilst completely unrelated things happened in my dream. I even once dreamed I was being driven around a large town and there were all these giant billboards each filled with a huge, single ATV logo.
I once dreamed I saw a dinner jacket standing at my bedroom door, no legs or anything coming out of the arms, and the ATV logo appearing in place of the face, the V twitching like a grinning mouth...
I was so glad when Central came along ... and then... "Central Presents..."