Hello. I am trying to find a website where I will post a zip file containing a pdf file and the website can host it and people can download it. I just want to know any good websites for hosting these files. No surveys, free service, ease of use, no pop ups, no sign up and not a lot of advertising. Anyways thanks! 
Some folks I know have started using dropbox. It gives them a direct file URL with no nonsense.
Dropbox is slowly becoming the de facto standard; there are also iphone / android apps for it, which has helped in its adoption.
Scribd is also used, as well as google docs with some helpful features, but both require sign ups as the one criterion from your list that is violated.
Dropbox is great! It really couldn't be any simpler, while having some really nice features - such as versioning your files, in case you accidentally overwrite or delete one.
With DropDAV you can even use it as a WebDAV server to easily synchronise files across multiple computers / devices. Very neat!
hum, i used to upload my file to 4hared but some says dropbox nice.. but i haven't tried it yet
The following is in french but it still do the job (more for sharing than hosting)
dl.free.fr
Max size per file :
1GB (Web)
10 GB (FTP)
No registration required
Retention = 30 days from the last download so that popular files can be retained very long
More info about it on:
Accueil - Tutoriel http://dl.free.fr