The publishing feature is on site collection level and upon activation all my sites in the site collection would have the media web parts, such as video active. My customer doesn't want that. She want's to enable video web part on one site only. Is that possible?
Since the WebPart Gallery is "Site Collection scoped", well it really is not, but there is only one Gallery per Site Collection (placed in the root web), scoping webparts to a smaller scope than Site Collection is not possible.
So for the Publishing related webparts, it is not possible to have them in some webs but not all, without the sites being in different site collections. Other publishing features, that are web scoped, is controlled by a web (site) scoped feature and hence can be controlled more granular
Administrators of a top-level Web site can determine which Web Parts are available to the users of sites in their site collection. http://office.microsoft.com/en-us/windows-sharepoint-services-it/managing-a-site-collection-web-part-gallery-HA001160854.aspx