ill chime in with what i have experienced. as others have said, length is just part of the equation. the particular board, boot size, and riding style should also be considered. im 5'11" booking in around 265. when buying my board i had to consider primarily a board that would be best for charging groomers and steeps. i like to jump but nothing huge, mostly natural hits when i find em. i dont often find myself jibbing through the park with the little 150lb kids. i know thats not my place. my sights were set on the Never Summer Heritage. I probably still would have gone with the Heritage if I could have found one locally in the size/width i wanted, however after a great discussion with a guy at Val Surf in North Hollywood he mentioned the Raptor. Turns out, the RaptorX 165 (wide) was a great fit for me. at the time i was rockin size 13 DCs, but those were terrible boots for me and ran really small (12 too tight and 13 a little too big). i am trying the new 686/New Balance 580 focus boas this year. size 11 fit perfect. hope it doesnt affect me on the wide board.
really what im saying here is that there are tons of factors to consider...and you might get it right, might not. demo days are the best to find the perfect ride for you.
as for recommendations based on your riding style/progression you might want to have a look at the Never Summer SL (or Legacy if you need a wider board). good all mountain board for you to start on. consider the 159 or 161 for your weight. if you dont need the wide consider the SL 158 or 161. you could always upgrade as your skill set improves or determine exactly what type of riding will dominate your time on the mountain.
I recommend Never Summer for you because of what you have mentioned. on one hand you wanted traditional camber for carving yet a rocker for the park and powder. with NS rocker/camber design you pretty much get the best of both worlds. im a heavy bastard and i couldnt sink the raptor in powder, even loading up on the front of the board. ive also never had issues with the board skidding out on me in hard turns. i have to work at that if i want to spray a buddy or unsuspecting noob with his ass parked in the middle of the run with a load of snow. at the same time ive never mistakinly caught an edge with that board. really is the perfect combination for my riding.
good luck in your pursuit.