I just drew a picture of my doom fortress but my scanner doesn't work. It's a flat, nondescript bit of land, and underneath the bit of land is my doom fortress. My guards would wear lightweight steel grey armour or civilian suits and menacing facial expressions. My personal guards would dress like the droogs from Stanley Kubrick's A Clockwork Orange.
I'd wear whatever the bloody hell I want to wear, because what's the point of being the leader of the world if you can't? And 'whatever the bloody hell I want to wear' is essentially Luke Skywalker's black ROTJ suit thing. Depends on the occasion though. My weapon of choice? Probably a flamethrower, because it creates...fire. Yeah.