Deep Sleep 1.2 is a freeware open source DashBoard widget that will transform how you use your desktop Mac. Incidentally with the release of version 1.2 it is now compatible with Mac OS 10.6.x according to the detailed clear user guide. I'm still on 10.5.8, so I can't speak from experience on this. I am using a mid 2007 model of the Mac Mini, and I can now put it into hibernation with one click and with no use of Terminal by me. Hibernation combines the advantages of Safe Sleep with shutting down your Mac i.e. it uses no more electricity than if it was turned off but your currently open applications are exactly as you left them once you awake your desktop Mac with one push of the On/Off button. Entering hibernation takes about 30 seconds---at first it appears to have simply gone into ordinary Safe Sleep as the little LED at the front of the Mac does the usual sleeping slow blinks several times before it goes out. On waking there is no startup clime when you push the On/Off power button, and waking takes roughly 30 seconds or so i.e. much faster than booting up from Off.
Some comments have queried the fact that on the very first occasion you click upon the installed widget it asks for you admin password. Well, I have LittleSnitch installed, and I have not been alerted to any attempts at outboard communication by the widget. Also it is open source so the source code is freely downloadable if you should wish to examine it for any possible naughty aspects.
Note that Deep Sleep will not work with some older models of desktop Macs, see the pdf documention for details.