Certificates themselves only make your services more marketable, they don't make you a better personal trainer.
Where do you plan to work? If it's at a gym, ask them what certificates they respect the most. Some organization will require specific ones, and others don't really care, and will give you more pay based on the number (not quality) of certificates. In that case you might as well get the cheapest ones you can.
If you going to market yourself to the general public, almost nobody you talk to will know the difference between NCCA and ACE. They might ask "are you certified?" (and they should), but that's about it. In this case, the decision is really up to you: what do you think will make you a better trainer? These certificates will only help get customers in the door, not retain them.
If you really, really want your question answered then ACE and NCCA are the two I hear mentioned the most and are probably the most recognizable. This is only my personal observation and yours might differ.