I've always liked persons of color (/ white persons) because it implies individuality and individual consciousness. "Persons of color" speaks to me as describing individuals who happen to have a certain trait, whereas "people of color" doesn't quite as much and "colored people" sounds like more of a defining language than a descriptive one.
Also, just as a kind of related topic, one thing that I have long been working on personally is cutting back on "you guys," "hey, guys," etc. when addressing mixed company. The problem is that, if I'm nervous or under pressure, that's what my mind defaults to. So in situations where I should be most cognizant of it, I tend to actually use it the most. And "you all" just doesn't hit my tongue right.