I have a Lowepro CompuDaypack, holds my 17" laptop, my D40, and 4 lenses including my 70-300. Also Has a nice little pouch for my mp3, nice organization inside with 2 waterproof zippered pouches. I have been able to put a change of clothes in mine also. It is super comfortable to wear even though fully loaded it's heavy. I've never had an aching back from it, I took it on a cruise with me and wore it for 6+ hours a day and was fine. And also easy to get through airline security, some friends had a different bag and had security issues,not being able to see through all the way, mine flew through no problem.