If the pack fits, wear it, especially since the Vapor KI ($170, granitegear.com) comes in "short" and "regular" sizes, can carry 30-pound loads, has 3,600 cubic inches of space, and is decked out with pretty purple detailing. The one downside of the Ki, however, is that it offers top-access only and has no lid. If you're a hyper-organized minimalist and don't need to burrow through your pack for that lost tube of sunscreen, this might be just fine. But if you like multiple entries, this limited access may start to make you crazy.
GoLite makes a featherweight 1 lb, 7 oz, 2,600 cubic-inch pack that can still hold up to 30 pounds of gear. For such a lightweight, the double-ripstop nylon Jam 2 ($125, golite.com) has plenty of fun features, like a front pocket with a watertight zipper, mesh shoulder straps, hydration tubes, and the comPACKtor, a compression system that'll cinch everything down.
Osprey's Kestrel 48 ($159, ospreypacks.com) is a do-anything, multi-use, multi-day pack that comes in two torso sizes and has an adjustable harness for a custom fit. With a raincover, straps to store a sleeping bag, ice ax loops, and pockets everywhere, this pack has its share of bells and whistles. It weighs in at 3 lbs, 14 ozs, with 2,800 cubic inches of roomy space.