I have a vision of the pack you need, but I'm not sure the vision translates into reality. Mountainsmith, for instance, used to have a pack in its lineup called the Explore that was a combination pack/computer case/briefcase—ideal for the urban warrior who likes to take the backwoods commute home. I got one four years ago and used it extensively while traveling and hiking to research my book on forest fires (shameless plug—A Season of Fire: Four Months on the Fireline's in America's West, available at Amazon.com). It has a generous 1,600 cubic inches of capacity, a slot for a notebook computer, pockets for the accoutrements of modern life such as wireless phone and PDA, even a "file folder" slot. It has bottle pockets but no hydration bladder (you probably could retrofit one).
Note the use of the past tense. Mountainsmith has quit making the Explore. BUT...you still can find it with a Google search, for around $90. So hop to it.
You might also find that a "regular" pack works just fine, with a few customizations by you. Gregory's G Pack ($139; www.gregorypacks.com) is essentially a simple bag equipped with a high-end suspension, allowing you to fit it out any way you wish. To help organize things, it has top and side pockets, even pockets in the waist belt. The G has room for a hydration bladder, and tie-ons across the back to hold any overflow. You'd probably want to get a separate case for the notebook computer, but something such as Case Logic's Padfolio Shuttle ($30; www.caselogic.com) would work well.
Lastly, Ultimate Direction's SpeeDemon ($120; www.ultimatedirection.com) offers you a hydration-ready pack that holds enough for your 24-hour jaunts (2,300 cubic inches) and gives you lots of storage options with side pockets, compartments attached to the waist belt, and a top pocket. This one's been schlepped by multi-day adventure racers across the globe, so at the very least should be well suited to your kinetic, go-go lifestyle.
Read more backpack reviews in Outside's 2004 Buyer's Guide .