In the past, I've felt in control by having each of my Hot Pot exercises in a folder along with all its related files: audio, video, images.... The links from the Hot Pot exo to the media files were all relative. I've been able to easily move these folders around from one server to another, to display the exo on Moodle or elsewhere, through the HotPot module, or QuizPort or Book. All the links worked everywhere.
Now I gather, I should be doing things differently by using a repository, or maybe several repositories. I've already been doing this with my Flash videos: I've uploaded them to YouTube and inserted them from there with an absolute link. That's been fine - I have relatively few videos - and YouTube seems likely to be around for a long time. However, I've got far more images and sound files and I'm not sure how to manage them elegantly, easily and not to have to redo all the links in the foreseeable future.
I've tried to display my Hot Pot exercises in Book on Moodle 2.4 and none of the media files appeared (they did in TaskChain). I'm experimenting with Stan's suggestion for using the JW Player for displaying a playlist in a Hot Potatoes exo. There too the playlist code requires an absolute link.
There are so many repositories (Moodle doc Repositories lists 13) I've no idea which one(s) to choose. What have other people done? What suggestions do you have - in particular as regards future proofing?