Lowepro CompuTrekker AW

Here is my Macbook going into the notebook compartment at the back of the bag. The Macbook is 13" when it's all the way in the bag there is room left to spare (see the other photo below) in the compartment, you'll be able to fit a 15" notebook in there.
There's plenty of padding and is secured via the zipper and buckle.
Just in case you're wondering, beside the decepticon sticker is a Linkin Park sticker.

Here's the built in tripod holder. To access you have to lift a flap which will expose a large pocket as well as the tripod holder/flap. In the pocket is a 70-300 IS USM lens to give a visual of the dimensions of this pocket.
Both these flaps are held in place by velcro. the Tripod holder/flap unfolds downwards which exposes a pocket like thing which you stick 2 of the 3 legs into. The rest of the tripod is secured via bungee cords and buckles. One in the middle of the bag and the other on the top of the bag. To secure the tripod to the bag, unclasp the buckles and separate the two pieces and lay the tripod between the pieces and clasp the buckle. There is a pinch type fastener on the bungee cord that allows you to control how secure against the bag you want the tripod to be. If this sounds confusing, don't worry, you'll get it when you see it, or maybe the photos below will help.
This means that you shouldn't put anything too fragile into the pocket that is revealed when you flip the tripod flap down. I put a large microfibre towel in there. So far I haven't broken anything because of the tripod.
I prefer the tripod being held in the center of the bag as opposed to the ones that mount the tripod off to one side of the bag. Those feel too unbalanced for my liking.

This pocket is situated on the front of the bag and above the "tripod pocket" mentioned in the previous section.
This pocket is quite deep. The photo is looking down into the pocket. You'll notice that there is pen slots, media slots, papers slot and a keyring snap. You can fit quite a bit in there. I've put in a mini umbrella, a gorilla pod, 2 pouches (1 containing cleaning stuff, the other containing batteries, CF cards and remotes), wallet, keys, mini notepad, hair brush, mints, biz card holder and there's still room in there. The zipper for this pocket is under a flap (weather protection) and sometimes makes getting into the compartment a bit of a hassle. I guess it's also harder for a potential pick pocket to get at your stuff while you're carrying it. A recent incident involving water makes me glad that this cover is there.

Here you can see an adjustable strap with a clasp over a loop. The loop is for attaching Lowepro lens cases or something similar that will fit. This loop is not rubbery so it will not stretch like the ones on the Slingshot 200AW (Check out my Slingshot 200 AW review lens this means that a monopod will not fit through it. (Yeah, I'm weird, I sometimes carry both a monopod and my tripod).
The adjustable strap is there to make sure that the bag is snugly secure whether there is something attached to the loop or not. To open the bag and get to your gear, you have to undo the clasps on either side. Added insurance against the bag getting unzipped and everything falling out.

The bag comes with more dividers but I took them out. All the dividers are held in place by some strong velcro and can be arranged however you like. here's what's in the bag (from left to right):
Lying down is a 70-300 IS USM hood reversed; above it is a 100 f2.8 macro; in the middle is 400d attached to a 24-105 f4L hood on properly; below it is a 25mm extension tube with a 50 f1.8 II on top of it; below that is a screw on type IR filter.
The big round one is a EFS 10-22 with hood reversed; below that is a 430 EX flash with flash head at 90 degrees and a stofen omnibounce below the flash head; below that is a kenko 1.4x teleconvertor (placed sideways). Below that is space for something...I'm going to put a 580 EX II flash gun in there when I get it.
In the two pouches below all the gear are the pouches for my cleaning stuff and batteries, remotes etc. Above those in the clear plastic compartment is my drop in filter holder. The above two clear compartments I rarely use because I have nothing to put in it.
When I'm carrying my laptop, the two pouches goes into the front compartment and my pouche that spans the length of the bag containing my laptop wires and stuff goes in that slot.

The "AW" designation means All Weather. Which means this bag has my favorite feature...the built in rain coat! This raincoat is attached to the bag so you won't lose it and is stored in it's own compartment located at the bottom of the bag. It's kinda concealed and the entrance to the compartment is fully velcro. Look for the orange tab and that's where you'll find the opening.
There is a pinch fastener on the draw string so you can cinch up the rain coat to fit snugly around the entire bag except the back portion because that's covered by your back.
The bag itself is pretty much drizzle resistant, all that padding absorbs a lot of water, I found this out the hard way.
Note: the rain coat cannot cover the whole bag if a tripod is attached to the bag.

This bag looks huge, and it is. It can fit A LOT of gear. Surprisingly and amazingly, it's not that bad to carry around. The shoulder straps are very thickly padded, the back of the bag has bulging padding to provide back support, there's a waist belt to keep the bag from bouncing and hitting your back and there's an elastic buckle that keeps the shoulder straps from slipping off your shoulders.
I love this bag! I walk around for hours with all my gear. You'll notice the bag is there but it's not painful.
If you change lenses often, I suggest you get a lens case like the Lowepro ones that can be attached to anything that the fastening flap will fit into so you can take it off the bag and put it on your belt or something. It can be a pain if you have to change lenses out of the bag, with all the buckles and zippering. Especially, with a monopod or tripod attached because you have to remove it to get to your gear.
Once again, I LOVE THIS BAG!
I get around the lens change issue by using lens cases!