If you really want a larger tank, my suggestion would be to go to a famous site that begins with an e and rhymes with day. I was just on there today and there are several people on there who are selling
complete set ups fish, corals, and all for about that price. There are a lot of great deals out there, even on this site in the classified section. I would go for it if I could talk my husband into it!
By the way, I am all for bigger tanks, but I have a 90 and I find that I am still very limited as to what I can have in the tank. I don't think that there is a difference between a 55 and a 90 as far as stock is concerned. No tangs, no angels, limited wrasse, you get the idea. If I was going to go bigger I would go 100+ but thats just me.
Sorry, didn't mean to be a buzz kill. If you love the tank, than go for it.