I am a super fan of IAMRUNBOX.
This bag offers it all and worths every Krona. Good quality material and great design.
I bought both 30L and 18L of this bag and couldn't be any happier.
18L Spin Bag: This is literally my every day and everywhere backpack. It has the perfect size for your daily needs. I take it everywhere I go to; university, grocery, picnic or swimming. It has comfortable padding and a secure pocket at your hand reach while hanged on one shoulder.
30L Spin Bag: Large enough to take all you need for a weekend getaway or a light journey alike. However, take good note that the compartment below is not fully detachable and personally would not recommend 30L for someone 175 cm or lower! (it might look sort of big and sketchy.)