I hope that some REI experts/employees might reply to this post as well as members.

I’m interested in a new pack and want to get some different perspectives. 

There are plenty of articles on the REI blog and other media but this “Conversations” platform is a valuable resource. Learning from other peoples’ mistakes and experiences is much easier and less expensive than trial and error. Thank you all in advance for your insight and assistance.

The goal is to find a backpack for long day hikes that has the capacity to pack for overnight trips. Things like a blanket, bivouac tarp, first aid supplies, food etc... need to fit. Pushing the envelope, I would like to be able to make a weekend hike with minimal gear (hammock and tarp with minimal accessories) in good weather conditions. 

The capacity range, from what I’ve read, appears to be about 38-50 liters. A lot of day hikers are unprepared for emergencies, but I don’t want to show up looking ridiculous like I’m heading out for one of the triple crown trails. Obviously, the best option would be to own 3-4 different packs, but I’m really trying to create a bag that is basically an overnight pack (light packing) that could be pushed for 2 nights, and doesn’t look ridiculous compared to the “book bags” many people carry when hiking. 

If you all could post your recommendations, with reasons for your bias, I would truly appreciate the input. It’s mostly about what liter capacity would be best, but if you want to recommend a specific pack that could be helpful too. Again, thank you all for your input.