I am kind of excited about the prospect of all the applications in Snow Leopard weighing in at much smaller sizes. I think that'll do good.

Mac apps I believe have somewhat fluctuated. When OSX first was released apps got kind of large and then as subsequent releases came they came down in size. One of the biggest changes that seems to be coming to Snow Leopard is file compression. That by itself will make things seem smaller the second item is the continued switch to vector based graphics instead of bitmap images. The difference between bitmap versus vector is immense. If you're not familiar with it vector images can scale to any size and can have layers, opacity, channels, and a lot more plus they tend to look cleaner and clearer.