That's a question I often make myself, always to the same answer!
I guess this victory as Germany, surprisingly flawless as it happened to be, is certainly my best performance, by normal standards (http://www.webdiplomacy.net/board.php?
gameID=168647#gamePanel).
But the game I'm most proud of is, definitely, this one: http://www.webdiplomacy.net/board.php?
gameID=106923#gamePanel
I still recall my anxiety in several key moments of it. A very unremarkable game up to 1910; failed invasion of France, failed attack of Germany, failed attack on Italy and, well, attacked by the three of them. But from 1910 to the end it became a mad effort to contain a Russian solo. In the beginning of 1915, for instance, I controlled Iberia, Marseilles, Munich and Trieste, deploying fleets at Nao and Aegean, and armies in Munich, Silesia and Trieste, having to coordinate with each and every member of our coalition.
Still don't know how I managed to survive it.