I use PayPal, Google, and Authorize.net currently. We are dumping Google in a few weeks - 1+ years of "1 in 5" chargebacks and poor (non-existent?) customer service. PayPal is best of breed but we do not use them as our primary payment handler; it's an option presented to customers upon checkout though.
+1 for Authorize.net. Paypal's Website Payments Pro is good too.
Consider the trade offs between better user experience if the payment process is on your site vs. not having to deal with PCI compliance with a hosted solution.
