Always always always take everything off!!!! That is just good gym etiquette, as a gym manager my biggest pet peeves are dumbasses who leave plates loaded on the bar. I hate this shit I'm not there to clean up after your lazy asses I'm there to run the damn place. Yep you hit a nerve with that one on me 
yup...as i put it, Im not your fuking mother so clean up after yourselves
its about respect and that goes for everyone even the women if they use the leg press etc then a 45 per side maybe heavy to them.
whats one more 45 a side you lazy ass bitches!!!

dont get me wrong when some dude say leave such and such on as im unloading its a fucking relief but still unload your weight if no one does...