I am right handed and unclip left first. I use TriGirl's logic about the stronger leg being my "push off" leg. When I started riding clipless I never thought about it, taking the left out first just seemed right. DH is right handed and usually unclips right first.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan