There's a book titled The Bandsaw Handbook that I'd recommend you pick up and read through.
I have a 17" saw that I can do everything from scrolling to resawing on. It's the most used machine in the shop when I'm doing furniture. A 14" saw is a good size for most people, Delta or Grizzly are good choices as are several others.
Another good source is Iturra Designs. His catalogue is as good as most of the bandsaw books out there. I'm not sure if you have to be a professional shop to get his catalogue, but I'd check them out.