I was out for 3 years and it only took a few trips to the mountain for get my legs back under me. You will be back kicking i no time only you wont have the endurance you used to and will wake up the next day feeling really old.
The newer boards ride longer than they are.
I'm similar size to you (175, 5'10" 9.8 boot) my 157 banana magic feels plenty long, good float and egde hold. i ride it all over the place though trees/chutes/park/pipe but i have a cheaper pow board for deep days.
I don't agree with others here about the La Nina it; is a fun board especially in NW poo, and not bad at all on regular groomers. I tried a bunch of the Lib boards out at baker the year before last before i bought my magic. the dark series and the la nina were my two favorites, but i wanted a twin.
Dude, suckin at somethin' is just the first step to bein' sorta good at somethin'