Good mid sized tank ?

[Acipenser]

yesterday I was at King Ed looking for stuff for my Nano build and made the mistake of going outside where the awesome stuff hides - The local's will know what I am talking about, tanks upon tanks and stands upon stands ! Maybe one day they will have a garage sale ?

Any way I have been planning on setting up a 50G I have had sitting around for a while, when I saw a couple of tanks that I thought would make a decent mid sized setups - everything from the 75g corner drilled to the 120g all 4 footers the other tank I quite thought would be a good reefer was the 30"x30" cube. I have a spot in mind that can accommodate a 6 footer but don't want to get into anything more than a 125g . I am looking to have a softies tank with a few reef safe fish - maybe a couple of pairs of designer clowns .