I like using a large beach bag myself. I agree with you on the zipping and I prefer it that way, but what I do is this - grab my largest zipped purse and put all 'important' items into it - then I put this inside the large beach bag (no zipper - just large opening at top). I find this useful for sweatshirts, water bottles, etc. that tend to come off during the flight that end up just being an extra thing to carry. Having somewhere to just 'throw' everything on the way off the plane is useful.