The elements of the solution include DesktopSweeper, a Mac shareware program that hides desktop icons, along with use of the Mac's Apple-Tab switcher (which is like Windows' ALT-Tab) and the Mac's Hide Other Windows feature which is bound to Apple-Option-H.
I too hate a cluttered desktop. A while back, I found a utility that automatically does what Jon Udell does manually using Apple-Option-H. Its called Spirited Away. It runs in the background, and hides all non active windows after a predefined amount of inactivity time.
Before I moved to the mac, in Linux I used to use Windowmaker, with one application in one work space. I'd have about 9 workspaces or so. The clutter on the mac desktop was too much for me, and spirited away helped a lot. Later I began using VirtueDesktop on the mac. Now that I am back to using Linux/ubuntu, I am back using windowmaker! :)