I needed a solution to carry my 40D, either my 15" HP Notebook or my 17" Toshiba Notebook, plus a few other necessities for hiking around locally or to be used as a carry-on when hopping on a plane to an exotic location. (I'm going to be visiting St. Lucia in July)
I looked around at my available options, and ended up choosing a backpack that I had never seen anyone else using before. The Tamrac Aero 80
aka Model 3380.
It has a top-loading PC slot, with the lower portion used for the camera equipment similar to the Tamrac Adventure 9 (which has a side-loading PC slot). I saw this as an advantage, since the PC can't fall out of the bag even if there is a zipper failure while walking. The opening also seems larger than the Adventure 9, which has had several complaints from those who can't seem to fit their 17" laptops inside due to the small opening. It has rubber weather sealing in case you get stuck in a downpour.
Here's a photo of my 15" HP Inside - plenty of room. The padding also seems to be much more substantial than my Targus dedicated laptop bag.
And my 17" widescreen Toshiba that barely fits (it's huge b/c of the 17" viewable monitor + an extra 3/4" of plastic around it, and it's about 1.5" thick). I would think a 17" macbook with its much slimmer profile would fit a lot nicer. This PC barely fits in any other 17" notebook case either b/c it's a bit oversized..
My 40D w/ 28-135mm IS USM, 70-300mm IS USM (non-DO), Sony HDR-HC5 Hi-Def Camcorder, charger, cables, 72mm CPL filter and lens caps. There are 2 zippered pockets on the lid for small items such as cables and extra memory cards. There is plenty of room for a pro-level DSLR or a 40D with a grip attached (my 40D in the picture does not have a grip). The padding is very substantial, I have no doubts that my gear is well protected. All of the padding is of course adjustable with velcro, or removable if desired. One thing to note, is that the depth of the camera area does taper slightly as you go toward the bottom of the pack. My 70-300mm fits great in the slot it's in and most likely has enough room for an inverted hood (I don't have one to test), but it gets to be a bit of a squeeze in the lower slot. It has a UV filter attached, so it's a few mm longer than just the standard lens.
This is probably what made up my decision to get this bag. It seems to hae the most available space for extras compared to any other backpack/slingpack that I looked at. The 40D (shown for scale) isn't stuffed in there either, the pack is wide enough for it to sit in there and zip easily. There are two mesh pockets against the back of this compartment, and a zippered mesh compartment in the front. The floor of this compartment is thick foam that's held in with velcro, so if you needed more room it is slightly adjustable or completely removable for an open backpack.
Loops for Tripod attachment (straps not included, of course)
There are mesh pockets on both sides and a large one on the back flap that hides the camera gear.
Overall, I'm very pleased with the room and the quality of the bag. It suits my needs perfectly. It's also very comfortable to wear. I haven't tested it on a trip yet, but it feels like the weight is well distributed and would be comfortable for extended wear. The nicely padded straps have non-skid backing on them so the pack won't slip off without you wanting it to, and each one has a loop sewn in for add-on packs to be attached. And the best part, it's available for ~$90. I consider that a steal since I was sold on the Adventure 9 prior to discovering this pack, and it's ~$130. That's also cheaper than my Targus bag for my notebook PC only.