Dakine Snowboard : Low Roller
Dakine has very durable bags with good price / performance. Board with bindings, and helmet/pants/jacket fit into the main bag easily and the boots are stored in extra exterior boot bags: smelly boots are separated from the other clothes
I second this recommendation. I got 2 for my wife and I before we went to SLC last year. It made the travel pretty easy. You can fit plenty in there. Just be sure to stay below the 50 lb max so you don't pay extra.