My favorite backpack is an old Dana Design pack I bought aeons ago. However my go-to daypack now is an LBT 3-day pack. They pretty regularly have them on sale for around $100. If you want a functional, durable (with a lifetime warranty), made in the USA backpack I can't recommend these enough.
LBT has this model on sale now in some pretty nondescript colors. I'd check it out. http://lbtinc.com/8k3a