trying to determine best solution for site build

Hi,
I'm considering getting a premium dedicated server from bluehost for a new buddypress site a client wants built. It's here:
http://www.bluehost.com/dedicated

My question is, is it cheaper to get a dedicated server and just add on to it OR is it better to use Amazon Web Services? The site will be social media focused and will have a lot of members and media (video, pics).

Please tell me your thoughts.

Corn