As I've mentioned many times before, I have a large "main playlist" of songs that I own that I like, and when I don't feel like listening to any one particular thing, I just put the big playlist on shuffle, and let Winamp decide what I feel like listening to. There's enough on there to play for more than ten days straight, 24 hours a day, without repeating: 3465 tracks so far. I open this playlist frequently enough that the "start Winamp" button I've assigned on my keyboard just opens this playlist automatically.
However, when I'm listening to a single album, I always listen to it in the original order, not shuffled. If the last thing I listened to was an album, and I open that massive playlist, the thing that starts playing is the first thing on there alphabetically: Betrayed Me by Adema. Luckily, it's not a bad song. I don't always remember to switch over to shuffle mode until after a second Adema song comes on and I realize something is off. So, it very well could be the song I've listened to more than any other in my collection. The only thing that makes me unsure is that it's only been there since 2003.
last.fm disagrees, though it's merely an incomplete and recent reflection of what I listen to, so not terribly accurate. According to my last.fm profile, the track I've listened to most is Mi Confesión by Gotan Project.
Currently listening: Adema—Betrayed Me, then Jewel—Sweet Temptation, and then I've queued up Gotan Project—Mi Confesión to skew my stats even further... :)