Plano 3700-series tackle boxes.
I can't recommend them enough. Cheap and versatile. When I started with them, I bought enough Plano to carry all my Orks, Marines, IG and Eldar (about the equivalent of 6 good-sized armies at that point) for the price of one GW army case and a spare set of foam inserts.
They come in a variety of divider configurations and depths, from 3/4" to 2". Most models are light enough that a few of them in a section won't hurt even if they bounce around. For heavier models, a thin piece of foam, like from the blisters, is usually enough to keep them from bouncing around. Titans are in the deep cases, with foam inserts cut. They even have trays which are half the size of the 3700 (can't recall their code number right now), so you could carry small cases side by side in the same dimensions.
They sell soft-sided and hard-sided carrying cases which keep the individual trays upright. I have a nylon shoulder-strap bag with large external pockets. The bag itself is large enough to carry 2 full armies with titans, plus a 1 1/2" notebook I keep with rules and army lists. The external pockets carry dice, templates, blast markers and snacks, with lots of room left over.
Plano Tackle WebpageThe various "Boxes" tab shows the hard-sided carriers. The various "Bags" tabs show soft-sided carriers. The "Stowaway Utility Boxes" shows the actual storage boxes.