I'm graduating with my PhD on May 19, and I'm pretty happy about that.
In my personal life, I'd have to say City of Blinding Lights at the first Vertigo show I attended, on 5/22/05. That night I realized my life was going to go back to normal after I'd been treated for pretty severe depression for a year, and had suffered from it for probably a year before being treated. It sounds kind of corny to say that the best moment of my life was at a U2 show, but when the confetti dropped and the band came out, something clicked inside of me, and I caught myself thinking for the first time in a long time "Everything's going to be all right."