many payment gatway available and they provide good services but paypal is is most of people acceptable for payment.
I would use paypal or 2checkout.com they are the top two in my opinion with my favorite being paypal.
i would suggest u to go with merchant account it is better than paypal ... becoz it has lots of hidden charges.....
Paypal is only good if you are selling physical products. Unless Paypal can be worst nightmare. PayPal's policy to deal with unauthorised transaction , Review process on random purchases are sometime most frustrated scenarios you may face. I have 3 eCommerce website for digital product and I get above $300,000 per year from paypal but out of them I guess 20% are being stopped, hold or refunded to buyers for unauthorised transaction. Yup! it depends on what industry you're applying it and for digital goods, Always choose options like plimus, digital river etc.
Try National Processing. Though US-based, I'm pretty sure they can cater to your needs. You'll have several facets of payment processes to choose from which would be very convenient for you and your customers.
there are lots of good suggestions, but I dont think that anyone has said "use as many as you have time to implement" paypal is good. I would put time into offering it. it doesnt matter that customers go to paypals site to make the payment, paypal users expect that. I would suggest that you add at least two payment options, eg a credit / debit card provider and paypal.