I would definitely choose PayPal as the main payment gateway for my site. This is the most popular mode of payment across the world and present in almost all countries. Moreover, PayPal is an established genuine player and hardly creates any issues. I have been using PayPal for the last three years or so and never encountered any problems in my account. So PayPal would be my first choice.
I would also like to add other payment options like Amazon Gift Cards, Payza etc. for the benefit of the members. I think the more payment options you have, the more members incline to join your site.
I would choose paypal because it is the most used payment processor, I would also choose payoneer and payza because paypal is not available in every countries and payoneer and payza are available in the countries where paypal is not available.