You might ask why I have only mentioned these two manufacturers. The answer is really quite simple, I've seen their drivers over a number of years in all kinds of kit. Celestion are often found in guitar amps of all makes and types. Remember the Orange 'W'bass cab that was all over stages with bass rigs a few years back? Well it's origial version is in that handbook. Then of course, how many Marshall cabs are out in the wild? (Not to mention the others!)
Fane speakers are and have been for years, the front end of literally thousands of PA and disco rigs. I've put a lot of Fane drivers into a lot of very different rigs and never been disappointed at the results.
There are many more expensive makes out there but to be frank, these two maufacturers are the best at surviving life on the road. Proof of that being the very fact that they are still out there, in much higher numbers than any other maker!
If you are going to make your own cabs, you simply won't beat these designs, or the drivers they were intended for.
You will notice that all of these are, by some standards, 'low power' but remember, it's not the number of watts you put out of the thing, it's the efficiency of the speaker and you will be surprised at the performance from these if you build the cabinets carefully and pay attention to good quality wiring. If you want more power, just add more bins. Putting a much higher rated driver in these cabs won't do anything positive for the sound quality, or the actual sound level for that matter.