if you have 800 bucks to spend, i would definitely consider taking a different approach. Firstly, i would get a better opinion on boards that would work well for you at thist point. I dont really know too much about board specifics so hopefully someone with a bit more knowledge on different boards can help you here. Even if the board that seems best for your riding at this point is not the top of the line 600 dollar stick you think you want, it will most likely serve you better than an advanced board and help you progress faster. You are not likely to be able to find a board that will last forever, and as you get better you will want to try out new boards and new technology that may come out in the future. This means that you should get a board that is right for you now, and worry about the future when you get there.
I do think that getting some good bindings is a wise choice tho, again someone can help you more than me here.
I would also suggest looking at a wide variety of brands, not just burton. Dont get me wrong burton has good products, but there is a ton of other stuff out there that is worth looking at, for example check out Never Summer, Rome, k2, Libtech, and Ride just to name a few.
Lastly, i would most definetly invest in boots. They are one of the most important aspects of riding, and ill fitting boots can ruin a day on the slopes. Even if this means you will have to buy a second pair for next year, the $$ are totally worth your comfort. Plus, if you dont spend 800 on a board you can make up the difference with some boots