Yes it can be done. So go buy a Mac.
Show Desktop - View Desktop
Command + F3 will show the desktop.
For other OS X keyboard shortcuts see also
http://support.apple.com/kb/ht1343
"Say I want to drag something from the desktop into an application but too many windows are open."
Open a "New Finder Window":: press [Command N] or Click on the top menu File>New Finder Window. Select "Desktop" as your new finder window. Now you have the desktop in its own window.
You can select how you want to view (4 ways) & arrange (9 ways) the desktop files & folders. You can change the size & move the Desktop Finder Window wherever you want. Leave it open or minimize it into the dock. It contains all the files & folders that are on the desktop. And you can drag things from that Desktop Finder Window into an application.
Show desktop button? Oooooo
You can open any application in another desktop. The same files & folders will be available.
With a Mac you are not limited to one desktop:
I use a track-pad. With a track-pad you can quickly swipe left with three fingers to see new blank Desktops (up to 5 separate desktops). There you can do anything you normally do on any other desktop. You can swipe back and forth between each desktop window without having to close the programs you have opened in each of the 5 desktops. Any changes made to files & directories in one desktop will be applied to all the desktops & those same files will be available in all desktops.
Also swipe up with tree fingers will separate all open programs, finder windows, etc on that desktop.
Then swipe up with two fingers will separate all windows of a specific program. Makes finding things on a desktop easy.
I could go on. Better stop there.