It will be very difficult to get a definitive answer as it's like asking what pair of shoes should you buy....
Here's some thoughts from a chap who knows a thing a two about being a big guy as well as being an iconic shaper:http://www.surfline.com/blogs/talking-d ... hig_27888/
Picking it apart, width is your friend, but as your relatively skinny for your height, draw the length out a bit rather than simply make the board thicker; your stance will be wider and, proportionally, a bigger board will smooth your style out a bit.
If it were my feet and I was buying a pair of shoes, then I would go for a 7'3" - 7'5" Speed egg type shape; it will have a nice amount of foam in the right places and will serve you well in a range of different waves. Adrian at Fluid Juice makes a nice one, as does Bro Diplock and they will listen to you enthusiastically and without prejudice (the same can't always be said about staff from generic surf boutiques or online stores) As you get better, it will also let you to develop your surfing, at which point you can go back to the shaper in a couple of years or so and let them know what's happening to see what they suggest next.
Do not listen to the marketing people or feel pressure to get a number of different boards for all sorts of waves while you are stil progressing. Stick with one board and learn how to ride it to the point where you are naturally thinking more about the wave in front of you rather than how the board is going to react.
Unless you are surfing all day every day from hereon in, which I presume you are not, hopping from one board to another whenever you go to the beach will do more harm than good - do not be tempted to be an amateur quiver-builder, regardless of what magazines and online forums will tell you; the affliction will occur naturally over time