For all those that have already begun dental school, would you recommend a backpack or messenger bag? I know that some people opt to buy all the books listed each semester, others just print power point lectures, others carry laptops to school everyday. In general a backpack is more comfortable if carrying a lot of weight. I am just curious what ya'll use and what you carry on you during a typical day. I would love to get by with just a professional leather messenger bag if possible.