Slappa Spyder Velocity. I nicknamed it the Tardis because its just so immense inside. It will easily swallow a 17 inch laptop, a change of clothes, an A4 folder, my entire pen, pencil and marker collection, DSLR.
Its the bag i take on weekend trips with all the above and more stuffed inside. Im using a 12 inch laptop now which frees up more space for the charger and an external hard drive.
Its extremely well made, with scuba type rubbery coating on the outside and the inside is extremely soft velvet sort of fabric. There are more nooks, crannies, pockets meshes than you will know what to do with.