While hiking with Zachary a while back, I asserted that out of the 5,000 or so songs in my iTunes collection, I could accurately identify 3 or 4 thousand of them after listening to the first ten seconds of the track. We agreed that in the name of science, I should test this boast.
In a moment of boredom just now, I tried it -- a ten-song sample from iTunes on shuffle, listening to the first ten seconds of each and then writing down my guess at the artist and title. I did pretty well, correctly identifying Abandoned Hospital Ship (Flaming Lips), Pretty As You Please (Ass Ponys), Night on the Sun (Modest Mouse), The Crawl (Placebo), Feeling is Wrong (Hail Social), The Last Last One (The Weakerthans), and Conspiracy Theory (Steve Earle).
I couldn't immediately remember the title of The Host by Built to Spill, nor 3030 by Deltron. And I thought Radiohead's Go to Sleep (Little Man Being Erased) was titled Stand Up, Sit Down (they have a track on that album called Sit Down, Stand Up).
So, approximately the same rate of identification that I claimed. But one would hope I'd have some recall given the massive amounts of time I spend listening.