I concur with Epoch. We actually use them primary on some sites. It's great if you can get the EU program, depending on where you are. Numbers work out better...
SEGpay is a good one to look at too. Also if you are looking to go multilingual and have lots of offshore options to bill with have a look at:
http://www.nocreditcard.com/
You can get your pages translated into other languages and setup the billing options to match the country the traffic is from. It's a very good deal.