The Kelty MAP 3500 is a very good pack (tactical), available at
http://www.amronintl.com/kelty-map-3500-three-day-assault-pack.html. Comfortable and durable and holds plenty of weight when necessary, but I tend to pack it out at 25 lbs for a 3 day hike and its ultra comfortable for that. Its available in multicam and several desert tan variants, I like the Coyote and Foliage Green for non-camo environments. Preferred pack of the USN SEALs, and I've spotted soldiers at airports carrying Kelty MAPs headed out on deployment, and they liked this pack. I've used one MAP for several years going on hikes and day hikes, and hold GHB stuff in two others, do a forum search and you'll find my reviews and endorsements. $120, with occasional price drops to clear excess inventory. I've gotten new MAPs for as little as ~$75.
No affiliation with or compensation from Kelty or Amron, just a happy customer.