Ortlieb are considered one of the best if not the very best. I use a set for touring and they are great. Worth the cost to protect your laptop and books. Although I would prefer to carry the laptop in a messenger bag - much less bumping around. For that I use a Chrome messenger bag.
http://www.ortliebusa.com/subcategory.asp?category=2
http://www.chromeindustries.com/bags/messenger-bags
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