To answer your question, I'd recommend Stripe.com or 2checkout.com. I have had bad experiences with Paypal.
On another note, these one line threads you keep creating to raise your post count are not doing you any good. If you are going to try and build a reputation here on HD, you are going to want to contribute quality posts. This question of payment gateways has already been answered a few times in previous threads, just do a simple search through the forums, or even Google.
Believe me, I'm not trying to bash you, I just am offering you some useful advise. You don't want to be one of the people here who reaches their post count and then just posts in the Marketplace section.