As Chris has mentioned, depends on what you're trying to accomplish
If you're looking for a solution with the most currency options, something like Paypal may work for you. Otherwise you may want to consider your own merchant account.
A merchant account will cost you more if your transactional volume isnt high (lets say under $1000 a month). But, if you're doing even half of that per month, a merchant account may very well be worth your time (savings realized from decreased admin as well as increased fraud protection)