On at least one website I manage the software has default options including several flavors of Paypal. I was wondering if someone knows of the best suggestion for a payment processing service as well known as Paypal, but who aggressively support conservativism.

I want to know this not just for myself but to others who manage websites that handle payments. What it comes down to is, is a reliable software/plug-in available to integrate with a conservative competitor of Paypal? Then we can promote that everyone does this because it's much less insane to do than custom programming.