Granite Gear Nimbus Ozone
That said, the Bora also falls in the sweet spot of pack sizing these days, so there is plenty of competition. One of the best is Gregory's Reality ($229; www.gregorypacks.com), which can handle 4,350 cubic inches in the medium size. I've had a Reality for several years, and it's still a great pack even though the newer models are much improved. It'll handle loads between 35 to 45 pounds nicely, packs well, and is plenty durable.
Another option to consider in this category is Granite Gear's Nimbus Ozone ($195; www.granitegear.com). It's about the same size as the Bora, and while it weighs a wispy three pounds, its suspension will manage 40-pound loads. Granite Gear stuff is always aptly namedin other words, it's very tough. Finally, you should also check out Mountainsmith's Auspex (www.mountainsmith.com), an enormously popular pack since it was introduced in 2001. The Auspex's 2004 incarnation sells for $230; it carries well, is pretty tough, and is easy to pack with 4,000 cubic inches of capacity (in its long-torso configuration).