Well, if you're looking for a light weight box that will hold a lot of flies & take a beating, I don't think you can go wrong with the boxes by Cliff Outdoors. Available in many configurations, they even have a box designed specifically to hold flies for a full day's fishing: a day box, if you will.
Another style of box is that offered by Meiho and Versus. These have clear, transparent covers over each compartment so you can see what's in the box at a glance. Available in different sizes these are real handy boxes - some are small enough to fit in a shirt pocket. That's just where I put my popper box when I'm fishing the bass ponds on those hot summer days.
All these boxes are available from The Contented Angler Fly Shop. Contact Joe & Amy Gablick there for advice when deciding which boxes are best for your needs.
If you're looking for tradition, beauty, & function in a fly box then I'd recommend a Richard Wheatley fly box. The Wheatley name is synonymous with fly fishing & quality. These boxes have been used by discriminating anglers for over 150 years. They are timeless. They are classy. They are the best you can get. Any one of their fly boxes would make a truly special gift for any angler.