Hmm, it all depends on how much you care about the laptop (even if they can be taken along on a trip, they are not really designed for travel, as they are rather fragile).
http
/www.dicota.com/catalog/product/view/id/409/s/bacpac-mission/category/9/#181=105&92=259
Something like this? Check the site, they got a lot of different formats for laptops, however their prices are rather high (worth it in my books but thats up to you).
There are basicly 4 formats:
Backpacks (pros is easy to use and rather comftable, cons is mostly that its hard to cover from rain, and also another problem is that if you "forget" that you have the laptop in the same bag as your books and start running for example, your laptop will suffer a lot from it).
Shoulderbags (pros are almost non existant as they are uncomftable and each step you take you transmit vibrations to the bag when it hits your body, but its cheap most times).
Trollies (Pros are almost all except price since you can in many cases use as a backpack, run it on wheels when on a flat surface and even carry in your hand if needed. Its normally more expensive and heavy).
Handbags/cases (Normally very good for the laptops durability, very bad for your health and wallet as its normally expensive as well).
Personally id go for a backpack or a trolly if i was you. Dicota is the only company that "I KNOW" that has a decent selection to choose from, and their quality seems good.
Im sure however that you can find a lot of other companies making those products thou, just i dont know any others that seem sturdy enoguht.