BUYING A SNOWBOARD PLEASE HELP?

Hello i am buying my first snowboard, i am size 12 boots, i am 176cms tall and weigh 180lbs. I have been looking at 2 snowboards the Burton Bullet or the Burton Blunt Wide, the Blunt is a 156 and the bullet is a 160 i intend to ride park and some mountain. Which do you think would accommodate my needs? Or alternativly could you recommend a snowboard that would be better and cheaper(preferably sold in New Zealand). Thanks