The ideal snowboard length varies depending the type of your weight, your height and the type of snowboarding you are into. Height is used by rental shops as a quick way to pick a board which will be 'about right' for you however the size and type of board you get will often not be perfect for you. If you are investing your hard earned money in a new setup we recommend using your body weight first, then height second to choose the right size snowboard. Your first step however should be to think about the type of rider you are and where you are looking to ride. Snowboards designed for jibbing or freestyle will differ in size to those for backcountry. Click the links below to check the ideal snowboard size for you.
If you have particularly large or particularly small feet then you need to consider the width of your snowboard. Pick a board which is too narrow and you could end up catching your toes or heels in the snow making it tricky to control your board. Pick a board which is too wide and you could find it difficult to initiate your turns or to make snappy edge to edge transitions. If your feet are average for your height then snowboard width tends not to be an issue.
Take a look at the breathability and waterproof ratings. Usually 5k, 10k, 15k and 20k (I forget the units used to measure them though) 20k being the shizzle!!! My pants and jacket are 20k on both ratings.
Air vents are useful too as it can get pretty warm when the sun is out.
Look at getting base layers and sub layers as well. Lots of thin layers as opposed to one super bulky jacket. You can always take a couple of thin layers off and store then relatively easily in your pockets if you get too warm. This works the other way as well.