As for breast implants - never really been interested in them. I wouldn't be getting cut open, risking infection and GA complications, getting bits of potentially dangerous plastic put in my chest just to improve business. It's too 'long-term' (they would be really deflated if you got them removed I imagine), costs too much (could think of much better things to spend a couple of grand on).
Although I do understand how some women get them though. I have naturally quite small boobs, but they at least are 'there' - if I was completely flat chested (like an AA or even AAA) I may have considered them.
Also, I think people in the western world get a bit pre-occupied with the sexual function of breasts, thinking it's their only function (!) Therefore excluding their most important function - feeding babies!