I really love the feast of the Transfiguration, and I've often reflected on it in these posts. To me it's just one of those very mystical feast days. In the same spirit I really love the Epiphany and the Presentation/feast of Candlemas.
To me the Transfiguration reveals that the Resurrection is not a historical event but a transcendent force. If it were merely a historical event, how could this Resurrection appearance--and surely it is one--occur before the Lord's Passion?
God makes use of the humanity of Christ to break into time and space. Raising this humanity to new life by the Spirit, this inbreaking arrives as the Resurrection of the Lord. It is the transcendent joined to the time and space of creation, or, more scriptually speaking, the marriage of heaven and earth.