If the boots are the 2010 models you got a pretty good deal on them if they're in the type of condition you would expect for only being worn once. If they're the 09 you might have only saved about $50 off of what's left in stores brand new. Of course it doesn't matter how good a deal you got if they're not comfortable...
No need to match the brand of all your gear, and there are lots of choices besides Burton that are of equal or greater value for your dollar.
If your boots are around an 11 or bigger you're going to want to get a wide board to avoid heel & toe drag. I don't think there is a truly right answer about what length to get so the variance in answers from calculators is kind of to be expected. I'm about your size and a 165 was a good starting point for me but you could go a little shorter, especially if you want to ride in the park a lot. I now ride boards from 159 to 176 and enjoy them all, each one is just a little bit different, not right or wrong. I'd say it's more important to get the board that is built for the type of riding you want to do than to sweat a few cm more or less, small changes in length really don't make as big a difference as the design of the board does.
Last edited by gibbous; 01-31-2010 at 06:56 AM.