Just got back from two trips using the Lowepro CompuTrekker for the following:
20D, (2) DS-125 strobes with arms, Ike Housing & one port, 3 lens', chargers, my 15" PowerBook, and a ton of cables...I was very happy to have all my vital underwater gear on my back. The only thing I checked on with my scuba gear was the handle. I'm submitting a picture in hopes it helps someone else. I spent a lot of time on Wetpixel listening to what others used and then got the CompuTrekker. This rig was super comfortable to carry. I was never asked about weight when checking my gear through TSA and it had a nice rain cover for those spontaneous tropical rains! I got the backpack that fits the 17" computer and was super happy with the padding for my laptop.
If you want a picture of the setup in my carry on bag, and this didn't post correctly, let me know.
Marc
Canon D20, Ike Housing, (2) DS-125, 60mm Macro, 10-22mm