Just make sure you pick one that allows you to separate the hosting of the product data from the hosting of the files. Otherwise you may be up for a hefty bandwidth depending on your site volume.
My opinion would be to base your decision more on the functionality of a system and see if it covers what you need it to do. As Opal mentions, you will be best off with a separate host for the actual media, but make sure the system sufficiently secures the files to prevent your shoppers merely sending the link to their friends… and at worst, that link going viral.
Demo stores are generally used to illustrate functionality and allow you to have a look at the codebase (where available).
Also with that size catalogue, make sure you can import your product data easily, else we’ll hear back from you in July when you’ve finished adding them
A 2 meg file is actually quite small so you could have the shoppingcart deliver the file for you via their digital delivery system and then you would not have to do anything yourself.