I have an Image Hosting site on a VPS with 1000GB bandwidth and 20GB space and my site is only using 5-10GB bandwidth a month and not even 500MB of space. The way I look at it is to have the Bandwidth even tho its not using that amount a month just incase your site kicks off rapidly. I promote my image hosting site through my Warez Forum and its getting busier by the week.

My image hosting site is hosted with http://vpsempire.com