I bought this bag about 4 years ago from the Chrome store in San Francisco. It's called the Chrome Mini-Metro and has pretty much been everywhere with me since then. Easily one of my cornerstone possessions, unfortunately its time is coming to an end.
By the end of college, this bag was beginning to feel a little cramped, especially when I had a binder or two and my netbook. With the advent of my iPad, the load is definitely lessened some, but I'm still finding it hard to cram my regular gear in with the binders I need for teaching. While on that topic, take a look at my daily gear; the iPad camera kit to transfer photos on the fly from my camera & even iphone; an iPhone charger, Zagg Z.Buds, a cleaning cloth, my trusty TI-89 calculator, some dry erase markers, my green laser (you never know...), an ink refill for my pen, red pens for grading, a duracell backup battery, iPhone cable, 4GB flash drive, aux stereo cable & RCA adapter, bluetooth headset, swiss army knife, and of course, my iPad.
As a replacement I've looked to competing company Timbuk2 and ordered their Superbad backpack. Like my other backpad, it loads from the top, but has a dedicated section for a laptop/iPad and should have a lot of space in it for my binders and other gear. Expect an update later this week.