I would say you are 25-80lbs short......if you want to follow the 1-2lbs LR per gallon theory. It's your tank, if you're not having any probs then you're probably OK.
I'm not having any problems other than about 15-20ppm of Trates but she thinks it looks a little bit bare. I am starting to agree with her and so I thought I'd ask the rest of the group.
My 29 gallon has about 35pounds in it. the 16 has around 15. but remember, it dosen't matter how many pounds you buy, its the rock. some types of rock are far lighter then others. with some types of rock you can fill a 55 gallon with as little as 40 pounds.
I have about 65 in my 55gal, but I want to get more! Two things you can never have too much of....light and live rock. Ok, well when the LR starts coming out the top of the tank maybe it is time to call it quits!