Check out Morton Buildings. They have a good line of designs and a "pole" barn is easier to finish out inside since all the structure is wood and easier to attach the interior onto when you decide to finish it out. Several friends of mine have made hangar homes from the Morton buildings with the aircraft below and the living quarters above. Very nice!!!
+1 on thinking about your size since it will fill up pretty quick. I built a 3,575 sq ft pre-engineered metal building (fully insulated) and I really like it although I had to erect standard studs inside when I built the office, kitchen and bathroom inside. Otherwise it cost 27K for the building and 8K for the concrete. I did the wiring, plumbing and 16x28 apartment construction inside. I will try to post a picture tomorrow.
2004 XR650L Heavily Farkled. 2010 KTM 990A Starting the Farkles.