I have a dropbox account. Whenever I try to use it with someone who does not have a dropbox account, they always tell me that clicking on the link takes them to a page where they are told they HAVE to sign up. They don't want to. I don't blame them, I have spoken to Dropbox about it and they are clueless or just don't ****ing care.
More and more I use
www.wetransfer.com. You can send up to 2 GB for free. NO registration. Add your files, attach recipient emails, add a message, hit send.
Regards,
Ty Ford