certainly not all of us have canopies! personally i like my tank as is, totally open--jbj flip top stand 4 in off the water for the lights and that's it. boy is it easy to get into the tank for maintenance. fortunately though i don't have any fish that are prone to jumping...and i don't have any fish that like chasing--so my jump risk is pretty low. when i was debating getting firefish i was going to do the eggcrate thing, but it does reduce light a lot so i opted for non-jumpers. i guess also, i'm fortunate in how i set up my sump--if a fish jumps out the back they'll likely just be highdiving into the refugium...but don't let them know that or they'll all be doing it to get at those bugs!
-leigh