If you're popping off a lip, usually people just jump. The shape of the lip loads your skis and when you pop, they give you a bit of a boost. However, on urban style, where the take-off is flat, it can take more of an ollie to get some pop. Probably depends on preference too and what kind of style you want to have. I usually just pop, especially if I'm spinning. (Although there certainly are situations where I ollie as well...)