Wetsuit wisdom?

Hi, I am thinking of investing in a wetsuit. Any wisdom out there? What style is the best...long, short, sleeves, no sleeves. Where is the best place to find one? Does wearing a wetsuit significantly improve your time? Last year I did the 1 mile swim in the Chesapeake Bay. Most people had wetsuits. The water temperature was 72 degrees, and I was not cold at all even though I did not have a wetsuit. Any thoughts? Swimmy :)