Okay, like Richie67 said, you really won't notice much of a difference. And, because you aren't past 6', I think you'll certainly be fine with the 154--that's what I would go with. ^^
What about me? I'm a size 9.5 boot, 172lbs and 5'7". I've heard the since the flex is rather soft on the Proto CT or new HD would that affect my board size? 154 or 157?