Think Tank Airport Security v2:
Definitely a 'max' size bag, fits a ton a stuff, and I've flown successfully with it all but once. Cathay Pacific got me with a weight limit of the bag empty! So I carried gear on my person (photo vest stuffed full, sling camera) and swapped housing to my gf's carry on etc. Took the bag on the plane almost empty.
I do find the sides like to bow out so I have a pair of straps I wrap around it between check in and boarding so it doesn't look too big.
Lowepro Whistler 450:
Just got this free, great Lowepro warranty, and agree with Aotus that it's heavy but carries well. Gear capacity is maybe 2/3 of the Think Tank roller + has outer compartment too. While no laptop slot, my 15" fits perfect in that outer 'wet' compartment, but I'd remove it before laying a loaded bag down to access gear. Works while flying though with a small laptop bag packed in my suitcase.
Its surprisingly narrow but its designed to carry skis etc on the sides. But that meant, when boarding late, I fit it fully loaded into a tiny overhead space last flight while people with much smaller rollers were lugging them back to the jetway to gate check on the full flight. Massive win.
Bonus: The camera box can be removed. Next non-photo trip I may use it as a normal bag. I've also seen someone put the box into a normal small roller, converting it to a camera roller for travel.
Kata CC-195:
Seems this no longer exists and Kata's been absorbed by Manfrotto. Designed as a pro camcorder bag, its shape is brilliant with a square cross section, and fits a 9" dome standing up as well as my laptop (in a padded sleeve) laying on top of the dividers holding the housing/strobes etc. Just wish it was a roller, would be my go-to for travel with the dome.
I also have 2 old Pelicans (I think 1550) that I don't travel with but are great for the boat here, where I do most of my diving/photo. Wish they were rollers though. Seriously would consider the 1510 or 1535Air.
Personal item is either Lowpro Flipside 300 (older version) or Photo Sport 200. The flipside is my go-to daily small camera bag (handles an slr + pro lens trinity very well). The Photo Sport is great for mirrorless gear or a subset of dslr gear. Fully expanded it can carry a ton of stuff, even my 15" laptop, yet it can be cinched down super small for activities like skiing.
Cheers,
Chris
Edit: Just thinking about this. Of the 3 bags I described, all can fit straight-in into an overhead bin, but the Think Tank (and rollers in general) are wide, taking up a lot of space across the bin while leaving a big gap between the top of the bag and the top of the bin. The CC-195 and Whistler both have rather square cross sections utilizing the space all the way to the top of the overhead bin and much less width across the bin. This can easily be the difference between having to gate check or not on a full flight.