REI Flash 45 works well for a great price at 50L for a large size - Once in awhile last year's model will show up on REI clearance site for about $65-$85 bucks. Decent stays and suspension but must be packed correctly for UL stuff at just over 2 lbs. Also ULA Ohm is a great pack as is the ULA Circuit. Try Elemental Designs Kalais or Aduro for the best suspension/weight ratio. The Kalais is only about 27 oz and is widely regarded as one of the best ul pack/suspension combos.