I'm in need of a airline carry on (US Air) large briefcase/boarding bag/backpack/shoulder bag combo.
It will house a 17 inch laptop computer, laptop mouse, power supply; a Scuba Diving Regulator Bag w. Scuba Gauges (12" by 14" by 4"); space for magazines and small books; an easy to access pocket for a file folder to go in (for airline tickets, passports, etc.); a small camera case (7" by 5" by 3") and small charger; and small telephone charger.
Any recommendations?
Thanks!

I would recommend the eBags Mother Lode TLS Weekender or its little brother, the Weekender Jr. Both have a laptop compartment, organizer panels for your accessories and a good size main compartment for your diving bag. The front pocket is easily accessible and can hold your books and magazines. The front panel also has a slash pocket for quick access to your tickets. Both convert to a backpack and can also be carried by a shoulder strap. I have put a lot of miles on my Weekender and I love it. It even fit under the seat on some flights. The bag itself is a bit on the heavy side but I haven't had much of a problem with it. However, I never carried diving equipment. :) Also, some people have complained about it being over engineered but I'm a bit obsessive about organizing so I don't mind all the pockets, panels, etc. Both bags are in the $70-$80 range on eBags website. I hope this helps.

Tom Bihn 's Western Flyer or Tristar sounds perfect for this. There a back compartment where you can get a nice padded laptop accessory sleeve and the front compartment can be separated into 2 to hold your Reg bag in one and books and stuff in another. They also have something called a Freudian Slip that is a nylon organizing envelope of sorts for files, documents, site maps and logs. However, Tom Bihn is pricey and even more so for something going to get abused on a dive boat.

Possibly a Red Oxx CPA Briefcase as it has plenty of room. The Tristar would be nice too!