There is one good on 108th street (HWY 100) in Milwaukee. its called aquatics unlimited lots of fresh water (like three walls full of tanks and lots of floor space is covered in ponds) and the other wall is salt water, with some crevices with extra salt water stuff.
The Pet Warehouse on 27th is better than the one on 108th (for salt water live stock IMO
) but both of those stores are big. (they have all types of pet supplies)
The one that I go to (and ironically I cant remember the name of is... but I just looked it up on google local and Its called Aqua Exhibits... its on Dr. Martin Luther King Blvd.) They are really nice, really cramped store, but MANY TANKS! also including a nurse shark tank (they have had these sharks for a long time).
Also Hoffers Tropic life pet, this place is also a great place for variety, however the price is usually higher, but they do offer free water testing.
thats all I can think of now... see if any of those ring a bell... If you are making the trip to milwaukee I suggest you stop at several store to compare them...