Since it sounds like you are still very open to suggestions... MY suggestion is to look around on the forums a LOT.
Find out what type of fish you really like and that will narrow it down some more.
Do you want a single species?
Look into some of the Mbuna. I always LOVE a demasoni tank. Beautiful tank and you can put a lot of them in a single tank. In fact it is encouraged to keep aggression down. Talk to Stan M., he has some good looking ones for sale. That would allow you to get a nice size group and keep the price down compared to a local fish store.
Peacocks and haps?
55 is about as small as I would go. My recommendation here is to make sure you get all males. It will help with keeping them all happy and also get as much color out of your fish as possible. If you look to local breeders, you could stock up the tank real well without too much cost. But, you would have to be patient as you would be buying small fish and they will take time to grow and color up.
Tangs
I dont have a lot of knowledge here, just a few species I have mixed in. But, you could set up a real nice tang tank. Some shellies to stick to the bottom.. some of the schooling kind to be at the top. Toss in some Calvus or Alto Comps. Hmmm... making me want to set up one myself.
Well... those were just some thoughts that come up real quick.
From experience... the best thing you can do is to research and find out what you like... and then come back to this thread and ask some more questions.
