well its all about your fish and tank setup really.
i dont like marine aquariums unless you have interesting fish ( stone groupers,lionfish,mandarin gobies...) you cant put very many fish in the tank either,so if you want more than five fish your gonna need ALOT of money,time,and space. i LOVE bichirs,arrowannas and pictus catfish for freshwater. now if want something in the middle you can have a brackish tank( a little bit of salt in a freshwater tank) you can get my personel favorite fish...a violet goby!! so it really depends if you have the money more than anything else,but either way i hope you the best of luck!!
