Out of the three of these CMS's, which would you say is the easiest to create themes for?

i think you sould ask which is more secure ?
phpnuke could be the larges but that makes it less securte with all these mods comeing for it which have bugs and people use these bugs to hack there way around.
plus i saw some cool themes for it and many people offer designing services for it so i would guess its the easyes to skin.
i personaly like http://www.vbportal.com/ which integrates with VB