I'm 5'10" 160 and picked up a 158. I LOVE it. I use it as my all mountain board and really don't play in the park with it at all. I have another board for that. I was going to go 155 until I rode a friend's 161 F1. After I was able to throw that board around with no problem I decided on the 158 for my SL. I have NO problems throwing it around in the trees.
Get the 161. I'm 6'2" and 200 lbs. I have both sizes (159 & 161). I got the 161 second. I rarely ride the 159 anymore. The reverse camber makes the board seem a couple sizes smaller than a regular cambered board anyways and you won't regret having the extra length.