I found myself asking the same question last year. I travel a fair amount with work and for pleasure. I also have plenty of gadgets and files with me at all times.
I spent some time checking out various brands, but by far the best I found was Swissgear. I have included the link to the bag I chose below.
I did go for this model to test the brand out with a view to going for a higher model at somepoint this year. The problem is I use this bag 6 days a week and it still looks and feels brand new.
It has a pouch/section for everything. Plenty of large space for last min purchases at the airport, one of the best laptop sections I have seen and the stuff pocket at the top is very handy.
Hope this helps.