Cybersource is an oft-overlooked option I'd recommend considering. We were going to go with the defacto AuthNet, but ended up choosing Cybersource for the added

Cybersource is an oft-overlooked option I'd recommend considering. We were going to go with the defacto AuthNet, but ended up choosing Cybersource for the added features (better recurring payments, international currency support) and the fact they gave us a pretty sweet deal (same price as Authorize.Net, which is their lower-priced option). I think a lot of these companies that typically target larger businesses are more willing to cater to startups these days to drum up new business.