Well it really depends on what country you are in. Paypal seems to change their rates from one individual I spoke with over this past week. Right now he said he was paying 2.9%, but he could get a lot lower with a merchant account since he is based in the United States.
With the electronic payment gateways you have a lot of choices depending on the country. In the United States, there are LinkPoint, Payflow, and Authorize.net/Cybersource that come to mind. Payflow is now owned by Paypal and you might consider getting a merchant account through that company as well.