For the avg joe an all termperature wax will do- put a thick coat on after your last lift ride and before you stash the board in your garage.  Remember to get the edges especially.  Edges tend to rust out in the off season.  Before you ride in the winter you will have to use a scraper-basically a piece of plastic with a straight, flat, edge to get the excess wax off.  Hot wax is far superior to the "quick wax," that is typically in liquid form and you apply on the slopes.  A good hot wax job will last for many more runs than the "quick wax."  There are waxes for different snow conditions but most boarders don't really know what the snow is going to look like until they get to the slopes and for this reason an all-temp wax is king.  Snow conditions also change throughout the day which is another reason to go with an all-temp wax.  "Fluorinated," refers to tiny bits of Teflon (polytetrafluoroethylene) that are mixed with the wax to make your board fiercely fast and spray bits of snow all over the skiiers.  Some fluoronated waxes are more expensive per gram than cocaine.

If your bindings are a couple years old check for rusted screws that should be replaced.  You can buy a binding repair kit for less than $10.  Alternatively you can hunt around a hardware store for the right pieces but you want stainless steel screws.  The cost is going to be comparable.  Pack the extra screws with your board tool in a zip lock and keep it in your jacket pocket or backpack.  Many repairs can be done right off the lift or at summit huts without having to find a patroller or trekking down to base to wait in line at the board shop.  Having fresh stainless screws means your bindings will be safer and you will not have to destroy your board in the event that you have to swap bindings.

You can also upgrade your board in the off-season with stomp pads to add more traction and a Burton capstrap.  Also consider board tools for tuning your board on the slopes (most are small ones that fit in your jacket pocket) and the required retention device (ie leash).  Avoid the "missing board," and lock your board especially overnight and when transporting on top of your car.  A great way to be ready for the unexpected is to ride with a slimline pack.  Da Kine makes great snowboard and skate packs to carry your lunch, your extra layers, and your iPod while riding.