How about paying directly through the credit card? What are the advantages of using a payment processor compare to paying a fee from a payment processor? I think we can save more if we pay directly using the credit card or the debit card.

You can very well try out alertpay.com

alertpay is good choise

MoneyBookers has been around for quite some time now, although I have no idea what their service fees are like. At the very least though, I am probably going to start accepting payments through Google Checkout within the near future, but I am researching some other services as well.

I like MoneyBookers and use it for my HoStInG bisiness.

after paypal moneybooker is the most used company in hosting industry and the other is 2CO

The best one is 2Checkout.com

I am just curious here, but what are the fees for MoneyBookers like compared to say Paypal or Google Checkout etc.?

I know that MoneyBookers has long been one of the most popular payment methods, but I have no clue how bad the fees are.

which one is the best in these module i.e. WorldPay, Paypal, 2CheckOut, Google Checkout ...

I quite like Nochex, don't think anyone has mentioned them here (although it's best to go for the merchant account, I think there's a setup fee).

Most customers tend to use Paypal, maybe it's just what they're used to so I think it's still best to keep Paypal as an option.

Paypal and 2CheckOut

There is Plimus, AlertPay, 2Checkout and much more.