Most of the airlines allow a snowboard bag to be checked as a normal checked bag, even though it exceeds the 'allowable' dimensions of a checked bag. It probably has something to do with the fact that the snowboard/ski season is a major source of income to the airlines in the otherwise 'slower than summer vacation' travel season. I say this because if you fly with a surfboard, you get charged $300 or so. So, seeing as snowboards are a little smaller than most shortboards in surfing, I couldn't understand any other reason there is such a big difference.
I've flown most of the major airlines coast to coast with my 165cm wheelie bag, and have never been charged more than the normal 1st checked bag charge. I only check in the wheelie bag which is packed with a 156cm board, bindings, boots, gloves....and so on. All my mountain gear including tools. Then I carry a backpack loaded with gear/clothes, and a carry-on suitcase loaded with all clothes.
If possible, only get nonstop flights. This cuts down on the nightmare chance that your gear won't arrive with you when you land. It's worth the extra $$ to not have to fight with the airlines about why your snowboard is in Texas, and you are in SLC.
One tip if you buy your gear and fly with it. Tape your board's edges with a couple layers of masking tape. Sometimes the baggage handlers hit the edges of your bag, and it can tear the inside of your bag up from your board's edges and the extra weight from all the other gear you pack in there.