If I set my files to Sort by file type in Windows Explorer, is there a way to change which order the various file types are arranged in? I would like to have all of my videos and images together respectively; but currently my videos are sandwiched between different types of image file.
No it does, but it won't group with the granularity you are looking for. There are a couple hundred "group by" fields, you may need to either look through them and see if there are any that are specific to a video or music type file and group by that or if you can find a program that can edit those properties you could use a blank one such as Comment and for example tag all your videos files as "Video", the different types of music files as "Music" then you could group by the comment field and achieve what your looking for.
So a little more information. You could write a powershell script to edit these properties. You would need to import the dsofile.dll library to edit the properties. Once that is imported you could search through the directories and you would just need some simple logic (like if this is this file type set the comment property to the correct type such as Video, or Music) Then you could group by comment and you would achieve your goal.