Gotta agree with the sentiments most have already echoed. The end of an era. Heck of a career. Been a huge fan of his since high school since I'm only 2 years behind him. Always idolized his lean body type and stride. Was always disappointing to see him injured so much over the course of his adult career, but that's life.
Still remember being in high school driving from Tampa to Orlando to see him win that Footlocker XC title against Webb and Hall. Stood right there at the finish line watching all three come across. Can still hazily recall the letsrun homepage when he ran his 13:55:45 or something to make the Olympic standard while in high school. Not to mention his world junior XC finish. So unfathomable for an American distance runner at the time.
As others have said, looking back it really did seem like the Golden Age of some kind. What all 3 of those guys did, while all being in the same class no less, is truly something special. They should all be given a lot of credit. At the very least they gave all us fanboys a lot of good memories.
Sad to see it come to an end...and as someone else so accurately pointed out...feel old.