By far the best modern propaganda machines would be the US and Serbian governments.
Though, when it comes to the means of showing off your military power, Russia, China and North Korea outmatch everyone. The Chinesse parade in 2009 was simply beautiful, while every Russian parade there is beautiful by its own tides. North Korean women are kinda funny to me with all the jumping and shit... xD
[youtube]http://www.youtube.com/watch?v=zVhzu7iIgtY[/youtube]