Well I agree that dropbox is easy, but it's also limited.
Space for example.
Also, if you're sending to a group of co-workers you don't have to upload the entire thing to the cloud. it'll transfer blazingly fast inside the LAN.
I think there's something in your product, but it doesn't have any selling points for me. Even if you make it as good as Dropbox or any other service, I won't change. For that, you need to be better than existing solutions.
Either be better or be different. Generic user facing file sharing - been there, done that.
Like djim said, storage space and bandwidth are non-issues.
May I suggest trying to get Sharefest popular within a niche? You may have to adapt to that particular niche, but I think it'll help you a lot.