The Maxpedition Rollypoly Backpack (mine is black) is a great value as a light duty day pack. The construction is first rate, the materials are strong yet lightweight, and the whole thing rolls up into a very compact form. I used mine during a weeklong trip to DisneyWorld in Florida in October, and it never let me down, accommodating all the ancillary stuff we needed for full days in the parks without adding extra bulk or standing out as inappropriately "tactical", even in black. Note that the shoulder straps are also minimalist, so you won't be able to comfortably carry really heavy loads, but that's not the intended purpose of this bag, and I think Maxpedition made the right trade offs between sturdiness, comfort, and light weight. In it's intended use as a light weight day pack the shoulder straps are perfect.

I highly recommended the Maxpedition Rollypoly Backpack.