I'd like to be able to do QuickTime so I suppose that a Darwin Streaming Server would be the best. Not really attached to any streaming engine yet. Only qualifications that I have are that it streams QuickTime and that you can reach the server via rtsp://yourdomain.com.
A long time ago I thought I'd seen a contrib (long before contribs.org) that was for the Darwin server but I haven't been able to locate it.