The Bergans daypack looks pretty good if slightly heavy, but should be durable and long lasting. I recently got myself a backpack in this size class from Macpac called the Rapaki 28+

http://www.gooutdoors.co.uk/rapaki-28-plus-p156996

http://www.macpac.co.nz/shop/en_nz/gear-and-clothing/packs/packs-day-packs/rapaki-28.html

It appears to be a well thought out backpack which crosses over from urban Laptop carry to a couple of days out in the mountains.