Totally depends on the manufacture. Check out the various web sites to see what the weight ranges for a given deck are. That said, if your going more towards the freestyle side of things, go for a shorter board. There are prolly some decks in the 150 - 153 range that would fit your weight.
BURTON | ELITE: I own a 2007 Burton Elite 155. I have used it for all mountain riding last season, and the first part of this one. It is decent anywhere you take it. Pipe, park, groomers, and double-blacks. However, it excels no where. Such is the case with any all mountain board. However, I find the Elite to be a bit better on the speed end of things than on the park end of the specturm. It is a little narrower, and a little stiffer than a pure freestyle deck, so your margin of error on landings isn't as large as it could be. At speed, it holds an edge well, but will start to chatter a bit when you REALLY start goinfg fast. Overall, it is a great all-mountain deck. However, I am selling mine.
NEVER SUMMER | SYSTEM: Awhile ago I decided I wanted a pure freestyle deck. I got the 155 System. It wasn't quite what I was expecting. It's a bit stiffer than most pure freestyle decks, but softer than then Elite. This deck is less stable at speed than the Elite, but more solid with butters, jumps, etc. Becuase it is a bit softer than the Elite, the System is basically an all-mountain deck that leans a bit more toward the freestyle side of things. I have tendency to ride switch a lot, hit a lot jumps, etc. The System is more geared toward that than the Elite is. So, I've made the choice to sacrafice some stability at speed for a little more flexibility.
And there is also that Rome Graft review I posted yesterday, too. Check that out.
size does matter on the company id prolly go with a 152-154 because those will give you the flex you need for the park but a 154 will give you the flex and the stability in and out of the park. if your not set on a park board yet then an almost twin board would be good. look into forums, ride and k2 as you did. but look for an almost twin board. and also look at the weight limits for them too. your gonna want to go with something in the middle for mid flex for the freeriding...