For slide-formatted pdf to ppt, I use a number of tools with varying results. Because the results are dependent on content -- as well as the initial setup of the ppt environment (backgrounds, etc.) -- I suggest you experiments with some of the free tools before moving on to the more costly solutions. For other than extracted slides ... I have not found an acceptable tool to automate the conversion of pdf files into PowerPoint. But I do use Pdf Converting Professional to export graphics to individual files and to recognize text using OCR. Then I cut-and-paste the wanted copies into my PPT format. I do my footnotes as the last slide -- then I can use hand-outs, projected talk slides, or make the entire package available on the web.
For video presentations ... I typically use the web to provide a web archive of the presentation -- that way, future audiences can watch a future event. For online presentation files ... To be frank ... I have found no tool to automate the converting of PowerPoint presentations into XML. That is all -- unless you want to convert your PPT files into a PDF or to create a video file from any presentation. What are your best tools? Please feel free to add any of the above to the comments -- and let us know which tools you use! Please note that all tools are free, provided that they meet my “fair use” guidelines.