There are a couple nice work-arounds to counter the two previously-noted side effects, produced by de-selecting raise_on_click. Older Unix users will probably find them familiar and like them more than veteran Windows users. One is "focus follows mouse" and the other is the ability to use a combintation of keyboard and mouse to move a window.
By clicking on System -> Preferences -> Windows, you're presented with the following screen. By selecting the first two check boxes and adjusting the slider, you can tweak the "focus follows mouse" function. You can also put that darned "Windows" key (or the Alt key) to work, allowing you to hold down the key, in conjunction with a left-click, to move a window.A lot of people have asked about disabling the "raise on click" feature. If you're one of them, I hope this and the previous post make your life just a bit easier.