Have you ever used a Mac? As mrklaw said, for media files, it does this very well already. It's not complete, but is close. I basically hardly never actually go through a file system to access music files or photofiles. Everything is handled by iTunes and iPhoto and whats called the 'iLife media browser'. This is transparent.
The best example is iPhoto. Your photo files are actually hidden away in a library that you cannot openly access via the file system. You organise everything in to events, albums etc in iPhoto, which is a front end for the hidden system.
Want to set a wallpaper? YOu can do it in iPhoto and select it and hit 'set as Desktop Background'. Or you can go to System preferences and under the Display Preferences, there will be an iPhoto drop down that shows all your albums and thumbs. Email? Same thing. As you write an email, you can click an icon that appears on the email window that opens a browser with all your iPhoto albums and thumbnails. iPhoto will also let you use a third party editing application. For example, let's say you use Photoshop to do edits. Open iPhoto, select the photo, and click 'edit in external application' (you can also set this to be default) - it then opens photoshop - when you hit save, it saves back into the iPhoto library.
These are also accessed by iMovie, iDVD, as is the iTunes library for combining them when making slideshows.
It's pretty well done, an is part of why Mac users enjoy as it is integrated fairly well system wide. It's not perfect, but it's pretty good.
Enthusiasm has waned a little, but not too much. I already have a Macbook Pro. What am I going to do with a MacBook? At least the iPad is different as a product.