this thread got me thinking, so I took some time and sampled most of the songs on my MP3 player to get a not-so-quick overview of the "signature intro" phenomenon.

Based on this short test, nearly ALL of the sampled songs had what I would call a signature intro. Very few if any started out with something that sounded like it was snatched from the main body of the song... but they all FIT the song seamlessly.

Now I'm wondering if the intros are part of the reason why I singled out these particular songs as favorites