Site Start is a great start up model that covers most requirements needed when you are setting up a web presence. It has enough space to hold files and has enough bandwidth to allow people to come and go without causing you concerns.
Site Plus is a medium placed plan for businesses who are looking to use larger type content management sites incorporating databases and personal blogs with lots of photos
Site Max give you the flexibility to have a large website with large traffic coming and going. Depending on your requirements, this plan will allow you to maximise your presence and still allow you a place to grow.