I already had an Eagle Creek Pack It Folder 18, and I love it. I posted a review for it too, but this is about the 15.

This item was purchased as a Father's Day present, but I made sure to try it out before it went in the gift bag! I just ordered another one in aqua and lime for myself today, because this folder is AWESOME. Most reviews don't mention packing dresses or skirts, which is what I wear on a daily basis (I could fit 3-4 full length dresses easily in this 15 Folder). These items of clothing tend to take up a lot of room in luggage, but this folder is a very welcome solution. They don't eliminate all wrinkles, but with a bottle of wrinkle release or even a spray of water here and there would be all you need for a trip. It's nothing like unrolling your clothes that come out of the bag needing to be ironed. This fact makes me smile from ear to ear - the vacation TRULY begins when you arrive at your destination.

That said, this Pack It Folder 15 fits inside my laptop backpack. We're not talking a hiking backpack either, this is a simple Jansport laptop backpack geared toward students. My only complaint is that these folders aren't sold in the color pink. Have a care, though - Eagle Creek's travel solutions become addictive. I'm replacing my previous luggage and packing methods with Eagle Creek as my budget allows, one piece at a time. Maybe I'm crazy, but there's something that gets me giddy about amazing my friends as I can get to anything in my luggage within seconds because of how well it's packed.