We work with two payment providers -- Sage Payments and Securenet. We prefer our customers use Securenet as that's a better deal for them, but it requires at least a three month transaction history on a different account to underwrite it, so its not suited for new users.
There are two varieties of PayPal -- the PayPal account people set up at paypal.com and pay through, and a standard merchant account that only supports credit cards (called PayPal PayFlow Pro).
Currently, we only support the PayFlow Pro merchant account, not the normal paypal.com account. We'll be adding paypal.com support eventually, but we haven't scheduled it for development yet.
Let me know if you have any other questions.