I have the Gregory Forrester at the moment, and it has served me well. It is super comfortable, was not too expensive (I paid around $170 on sale), and is still in great condition after many trips using it. My next pack will be an Arc'Teryx Naos, but I would avoid those unless you can get a really good discount or just have piles of money sitting around.
As far as brands to look at, the relatively large higher end backpacker crowd type companies are Arc'Teryx, Osprey, Gregory, Marmot, REI, GoLite, and Granite Gear. I'm sure I am forgetting some, but those should be a good start.
Fit is super important with a backpack. Every backpack company will make a pack that fits your criteria, but not everyone will make one that is comfortable to you. Your best bet is to wander into a specialty outdoor retailer and talk to someone in the backpacking area about pack fit. Do not bother with a regular sporting goods store. The employees there usually are not backpackers and will not be able to help much. REI is usually a safe bet, and they have the tools to measure what size pack you will need, along with weighted sacks so you can see what the pack feels like when it is loaded up. They will usually also let you pack your actual gear in the bag so you can see how it feels with what you actually own. Take any recommendations that you get from people with a grain of salt, since an awesome pack may feel horrible on your back. Just try out a bunch from different manufacturers and settle on one that you like the fit.
For lots of pockets and organization, good luck. The backpacker (not hunter, sportsmen, etc.) type companies make some awesome, high quality, super comfortable, and light packs, but organization has never been a priority from what I have seen. More pockets means more fabric and more zippers, which means more weight, which is the opposite way that most of them are going. You will usually have a main compartment, a lid pocket or two, and one or two external zippered pockets. The one nice thing a lot of the companies are starting to do is include small zippered pockets on the hip belt, which is incredibly useful for knives, flashlights, and other small gear. You might also have some external straps and mesh water bottle pockets. What I do is pack my stuff that needs organization in other lightweight organizing sacks or containers and then put those in my pack. It adds weight, but saving the frustration of rooting through my pack is worth it to me.
Also, by some sort of divine coincidence, I just got done writing an article on
packing a backpack. I'll have one up about fitting a backpack soon.
