My wife and I each use an Aqua Lung Deep See Travelok 2000 for our checked luggage. Best bags we've ever owned. Large capacity, rigid body, two internal pockets, no external pockets to tempt baggage handlers except for a zippered envelope pocket we don't use when the bags are in the air, over-sized wheels, rubber bumpers on the corners, rubber feet on the bottom for stability and the pull handle extends incrementally to accomodate any preference.
The dual zippers are backed off the edge by about an inch for further protection and the whole bag locks down tight with a single lock looped through the zipper pulls and attached to a D-ring, which is then secured underneath a velcro flap. (We tossed the included padlocks and instead use TSA compatible combination/key locks.) There are large padded grip handles on the top, side and bottom to help with loading and unloading.
These bags are well-designed and well-built with rugged materials all the way around and easily hold all our dive gear and a whole lot more.
On the front of the bag there's a very small embroidered turtle that blends in with the rest of the bag and is actually kind of hard to make out. Otherwise, there's nothing to suggest that it's dive luggage but it's obviously a high-quality bag.
For our carry-on bags, we each use an Akona AKB 176 Carry-On with the optional reg bag. The latter is designed to fit in the former's lower external pocket, saving space internally for whatever else you bring on the plane, which in my case is a prescription mask, log book, headphones, sounddock and laptop, which slides into an internal padded sleeve. There's an upper external pocket for smaller stuff like my point and shoot camera, passport, sunglasses, pens and the like.
This setup has worked very well for us on many a dive vacation as well as just traveling in general. Most of my life I've been too cheap to buy quality luggage, but when I started diving I thought it was time to make the investment. The pain to my wallet is now a distant memory, and I must admit that I should have done this a long time ago.