I made my own daypacks, blending the features that I liked from several packs and leaving out the features that I didn't like. The one piece of advice that you are likely to get is to wait until you get your gear together before you select your pack. The other piece of advice that I will give is to make sure that your pack is properly sized for your torso. I have a long torso for my height and most regular packs are too short for me. If you can find a store with some knowledgeable people, get some recommendations and try them on. Learn how to adjust the belt, shoulder straps and load lifters. I didn't have a pack with load lifters until recently and I was surprised at the difference that they made. I suspect that your overnight gear, even if it's minimal, will still be more than a daypack will handle.