well, a 55 gallon is a nice tank. i have one myslef. but i see a few things that i would change if i was setting it up. felt i would tell you and give you some constructive critisism.
first i see that you have what appears to be crushed coral. which alot of people start with, and alot of people have, and alot of people still do. The problem with crushed coral is it can lead to high nitrates if not taken care of properly. so unless you plan on vacuming it all the time, id consider a switch to live sand.. there are alot more benifits to live sand woth looking into, one being that it looks alot better.
second, i see that you are running a undergravel filter. again another nitrate factory. id remove it. it really us more hassel than its worth. and honestly not needed.
third, you dont really need the power filters on the back, they arent bad, good for running carbon, and extra flow in the tank. but they arent needed like the lfs might suggest.
fourth, get more live rock, its expensive i know, but get good cured, quality live rock. it will filter your tank better than both those h.o.b filters will, and make the tank more natural, and give the fish places to hide.
those are just some quick suggestions i have. in no way am i trying to be rude. you got the makings for a good tank. those are just some things i could see that would help you improve it.
you also might want to look into adding a sump and a refugium to the tank.