While browsing the General Discussion forums the other day, I noticed a recently-resurrected 2007 thread collecting players' oldest screenshots. Due to the age of the thread, some of the links (mostly on the first two pages) are dead and gone, which was really disappointing because some of them sound great, but there are plenty of good ones. Among the best are the character creation screen during beta, the old Troll epic mount, and -- according to Gorhendizzle of Bloodhoof on page 5 -- the first publicity screenshot Blizz ever released. I don't know whether that's true, but trying to figure out what the screenshot is of is driving me nuts. It looks like Elwynn, but I can't tell where.
My own oldest screenshot (see above) is fairly tame by comparison; I had just turned 41, and was proudly astride my new kodo on a starry night outside Orgrimmar. What (if anything) prompted you to start snapping ingame pictures? Are there any historical gems buried in your own screenshot folder? Search your hard drive; you know it to be true.